Prepare Spark release v3.0.0-preview-rc1

### What changes were proposed in this pull request?

To push the built jars to maven release repository, we need to remove the 'SNAPSHOT' tag from the version name.

Made the following changes in this PR:
* Update all the `3.0.0-SNAPSHOT` version name to `3.0.0-preview`
* Update the PySpark version from `3.0.0.dev0` to `3.0.0`

**Please note those changes were generated by the release script in the past, but this time since we manually add tags on master branch, we need to manually apply those changes too.**

We shall revert the changes after 3.0.0-preview release passed.

### Why are the changes needed?

To make the maven release repository to accept the built jars.

### Does this PR introduce any user-facing change?

No

### How was this patch tested?

N/A

Closes #26243 from jiangxb1987/3.0.0-preview-prepare.

Lead-authored-by: Xingbo Jiang <xingbo.jiang@databricks.com>
Co-authored-by: HyukjinKwon <gurwls223@apache.org>
Signed-off-by: Xingbo Jiang <xingbo.jiang@databricks.com>
diff --git a/R/pkg/R/sparkR.R b/R/pkg/R/sparkR.R
index cdb5909..dc1d1b2 100644
--- a/R/pkg/R/sparkR.R
+++ b/R/pkg/R/sparkR.R
@@ -337,7 +337,7 @@
   # Check if version number of SparkSession matches version number of SparkR package
   jvmVersion <- callJMethod(sparkSession, "version")
   # Remove -SNAPSHOT from jvm versions
-  jvmVersionStrip <- gsub("-SNAPSHOT", "", jvmVersion)
+  jvmVersionStrip <- gsub("-preview", "", jvmVersion)
   rPackageVersion <- paste0(packageVersion("SparkR"))
 
   if (jvmVersionStrip != rPackageVersion) {
diff --git a/assembly/pom.xml b/assembly/pom.xml
index ef916fb..69efac5 100644
--- a/assembly/pom.xml
+++ b/assembly/pom.xml
@@ -21,7 +21,7 @@
   <parent>
     <groupId>org.apache.spark</groupId>
     <artifactId>spark-parent_2.12</artifactId>
-    <version>3.0.0-SNAPSHOT</version>
+    <version>3.0.0-preview</version>
     <relativePath>../pom.xml</relativePath>
   </parent>
 
diff --git a/common/kvstore/pom.xml b/common/kvstore/pom.xml
index f042a12..b19380d 100644
--- a/common/kvstore/pom.xml
+++ b/common/kvstore/pom.xml
@@ -22,7 +22,7 @@
   <parent>
     <groupId>org.apache.spark</groupId>
     <artifactId>spark-parent_2.12</artifactId>
-    <version>3.0.0-SNAPSHOT</version>
+    <version>3.0.0-preview</version>
     <relativePath>../../pom.xml</relativePath>
   </parent>
 
diff --git a/common/network-common/pom.xml b/common/network-common/pom.xml
index 2ee1780..4000f92 100644
--- a/common/network-common/pom.xml
+++ b/common/network-common/pom.xml
@@ -22,7 +22,7 @@
   <parent>
     <groupId>org.apache.spark</groupId>
     <artifactId>spark-parent_2.12</artifactId>
-    <version>3.0.0-SNAPSHOT</version>
+    <version>3.0.0-preview</version>
     <relativePath>../../pom.xml</relativePath>
   </parent>
 
diff --git a/common/network-shuffle/pom.xml b/common/network-shuffle/pom.xml
index a6d9981..f144b70 100644
--- a/common/network-shuffle/pom.xml
+++ b/common/network-shuffle/pom.xml
@@ -22,7 +22,7 @@
   <parent>
     <groupId>org.apache.spark</groupId>
     <artifactId>spark-parent_2.12</artifactId>
-    <version>3.0.0-SNAPSHOT</version>
+    <version>3.0.0-preview</version>
     <relativePath>../../pom.xml</relativePath>
   </parent>
 
diff --git a/common/network-yarn/pom.xml b/common/network-yarn/pom.xml
index 76a402b..b355b29 100644
--- a/common/network-yarn/pom.xml
+++ b/common/network-yarn/pom.xml
@@ -22,7 +22,7 @@
   <parent>
     <groupId>org.apache.spark</groupId>
     <artifactId>spark-parent_2.12</artifactId>
-    <version>3.0.0-SNAPSHOT</version>
+    <version>3.0.0-preview</version>
     <relativePath>../../pom.xml</relativePath>
   </parent>
 
diff --git a/common/sketch/pom.xml b/common/sketch/pom.xml
index 3c3c0d2..5175e00 100644
--- a/common/sketch/pom.xml
+++ b/common/sketch/pom.xml
@@ -22,7 +22,7 @@
   <parent>
     <groupId>org.apache.spark</groupId>
     <artifactId>spark-parent_2.12</artifactId>
-    <version>3.0.0-SNAPSHOT</version>
+    <version>3.0.0-preview</version>
     <relativePath>../../pom.xml</relativePath>
   </parent>
 
diff --git a/common/tags/pom.xml b/common/tags/pom.xml
index 883b73a..ca6de22 100644
--- a/common/tags/pom.xml
+++ b/common/tags/pom.xml
@@ -22,7 +22,7 @@
   <parent>
     <groupId>org.apache.spark</groupId>
     <artifactId>spark-parent_2.12</artifactId>
-    <version>3.0.0-SNAPSHOT</version>
+    <version>3.0.0-preview</version>
     <relativePath>../../pom.xml</relativePath>
   </parent>
 
diff --git a/common/unsafe/pom.xml b/common/unsafe/pom.xml
index 93a4f67..ad2ba66 100644
--- a/common/unsafe/pom.xml
+++ b/common/unsafe/pom.xml
@@ -22,7 +22,7 @@
   <parent>
     <groupId>org.apache.spark</groupId>
     <artifactId>spark-parent_2.12</artifactId>
-    <version>3.0.0-SNAPSHOT</version>
+    <version>3.0.0-preview</version>
     <relativePath>../../pom.xml</relativePath>
   </parent>
 
diff --git a/core/pom.xml b/core/pom.xml
index 38eb8ad..19e6735 100644
--- a/core/pom.xml
+++ b/core/pom.xml
@@ -21,7 +21,7 @@
   <parent>
     <groupId>org.apache.spark</groupId>
     <artifactId>spark-parent_2.12</artifactId>
-    <version>3.0.0-SNAPSHOT</version>
+    <version>3.0.0-preview</version>
     <relativePath>../pom.xml</relativePath>
   </parent>
 
diff --git a/docs/_config.yml b/docs/_config.yml
index 57b8d71..b520819 100644
--- a/docs/_config.yml
+++ b/docs/_config.yml
@@ -14,8 +14,8 @@
 
 # These allow the documentation to be updated with newer releases
 # of Spark, Scala, and Mesos.
-SPARK_VERSION: 3.0.0-SNAPSHOT
-SPARK_VERSION_SHORT: 3.0.0
+SPARK_VERSION: 3.0.0-preview
+SPARK_VERSION_SHORT: 3.0.0-preview
 SCALA_BINARY_VERSION: "2.12"
 SCALA_VERSION: "2.12.10"
 MESOS_VERSION: 1.0.0
diff --git a/examples/pom.xml b/examples/pom.xml
index a099f1e..f37f059 100644
--- a/examples/pom.xml
+++ b/examples/pom.xml
@@ -21,7 +21,7 @@
   <parent>
     <groupId>org.apache.spark</groupId>
     <artifactId>spark-parent_2.12</artifactId>
-    <version>3.0.0-SNAPSHOT</version>
+    <version>3.0.0-preview</version>
     <relativePath>../pom.xml</relativePath>
   </parent>
 
diff --git a/external/avro/pom.xml b/external/avro/pom.xml
index ba6f20b..60c5f80 100644
--- a/external/avro/pom.xml
+++ b/external/avro/pom.xml
@@ -21,7 +21,7 @@
   <parent>
     <groupId>org.apache.spark</groupId>
     <artifactId>spark-parent_2.12</artifactId>
-    <version>3.0.0-SNAPSHOT</version>
+    <version>3.0.0-preview</version>
     <relativePath>../../pom.xml</relativePath>
   </parent>
 
diff --git a/external/docker-integration-tests/pom.xml b/external/docker-integration-tests/pom.xml
index aff79b8..0f0176a 100644
--- a/external/docker-integration-tests/pom.xml
+++ b/external/docker-integration-tests/pom.xml
@@ -22,7 +22,7 @@
   <parent>
     <groupId>org.apache.spark</groupId>
     <artifactId>spark-parent_2.12</artifactId>
-    <version>3.0.0-SNAPSHOT</version>
+    <version>3.0.0-preview</version>
     <relativePath>../../pom.xml</relativePath>
   </parent>
 
diff --git a/external/kafka-0-10-assembly/pom.xml b/external/kafka-0-10-assembly/pom.xml
index f2dcf5d..8442c46 100644
--- a/external/kafka-0-10-assembly/pom.xml
+++ b/external/kafka-0-10-assembly/pom.xml
@@ -21,7 +21,7 @@
   <parent>
     <groupId>org.apache.spark</groupId>
     <artifactId>spark-parent_2.12</artifactId>
-    <version>3.0.0-SNAPSHOT</version>
+    <version>3.0.0-preview</version>
     <relativePath>../../pom.xml</relativePath>
   </parent>
 
diff --git a/external/kafka-0-10-sql/pom.xml b/external/kafka-0-10-sql/pom.xml
index 693820d..cceace3 100644
--- a/external/kafka-0-10-sql/pom.xml
+++ b/external/kafka-0-10-sql/pom.xml
@@ -21,7 +21,7 @@
   <parent>
     <groupId>org.apache.spark</groupId>
     <artifactId>spark-parent_2.12</artifactId>
-    <version>3.0.0-SNAPSHOT</version>
+    <version>3.0.0-preview</version>
     <relativePath>../../pom.xml</relativePath>
   </parent>
 
diff --git a/external/kafka-0-10-token-provider/pom.xml b/external/kafka-0-10-token-provider/pom.xml
index 01ca96b..744423a 100644
--- a/external/kafka-0-10-token-provider/pom.xml
+++ b/external/kafka-0-10-token-provider/pom.xml
@@ -21,7 +21,7 @@
   <parent>
     <groupId>org.apache.spark</groupId>
     <artifactId>spark-parent_2.12</artifactId>
-    <version>3.0.0-SNAPSHOT</version>
+    <version>3.0.0-preview</version>
     <relativePath>../../pom.xml</relativePath>
   </parent>
 
diff --git a/external/kafka-0-10/pom.xml b/external/kafka-0-10/pom.xml
index d11569d..0e1d95c 100644
--- a/external/kafka-0-10/pom.xml
+++ b/external/kafka-0-10/pom.xml
@@ -21,7 +21,7 @@
   <parent>
     <groupId>org.apache.spark</groupId>
     <artifactId>spark-parent_2.12</artifactId>
-    <version>3.0.0-SNAPSHOT</version>
+    <version>3.0.0-preview</version>
     <relativePath>../../pom.xml</relativePath>
   </parent>
 
diff --git a/external/kinesis-asl-assembly/pom.xml b/external/kinesis-asl-assembly/pom.xml
index 0ce9223..ae75d1b 100644
--- a/external/kinesis-asl-assembly/pom.xml
+++ b/external/kinesis-asl-assembly/pom.xml
@@ -21,7 +21,7 @@
   <parent>
     <groupId>org.apache.spark</groupId>
     <artifactId>spark-parent_2.12</artifactId>
-    <version>3.0.0-SNAPSHOT</version>
+    <version>3.0.0-preview</version>
     <relativePath>../../pom.xml</relativePath>
   </parent>
 
diff --git a/external/kinesis-asl/pom.xml b/external/kinesis-asl/pom.xml
index 7d69764..e284c52 100644
--- a/external/kinesis-asl/pom.xml
+++ b/external/kinesis-asl/pom.xml
@@ -20,7 +20,7 @@
   <parent>
     <groupId>org.apache.spark</groupId>
     <artifactId>spark-parent_2.12</artifactId>
-    <version>3.0.0-SNAPSHOT</version>
+    <version>3.0.0-preview</version>
     <relativePath>../../pom.xml</relativePath>
   </parent>
 
diff --git a/external/spark-ganglia-lgpl/pom.xml b/external/spark-ganglia-lgpl/pom.xml
index a23d255..190fffd 100644
--- a/external/spark-ganglia-lgpl/pom.xml
+++ b/external/spark-ganglia-lgpl/pom.xml
@@ -20,7 +20,7 @@
   <parent>
     <groupId>org.apache.spark</groupId>
     <artifactId>spark-parent_2.12</artifactId>
-    <version>3.0.0-SNAPSHOT</version>
+    <version>3.0.0-preview</version>
     <relativePath>../../pom.xml</relativePath>
   </parent>
 
diff --git a/graph/api/pom.xml b/graph/api/pom.xml
index a18c529..953d035 100644
--- a/graph/api/pom.xml
+++ b/graph/api/pom.xml
@@ -23,7 +23,7 @@
   <parent>
     <groupId>org.apache.spark</groupId>
     <artifactId>spark-parent_2.12</artifactId>
-    <version>3.0.0-SNAPSHOT</version>
+    <version>3.0.0-preview</version>
     <relativePath>../../pom.xml</relativePath>
   </parent>
 
diff --git a/graph/cypher/pom.xml b/graph/cypher/pom.xml
index 12b3832..865a1bc 100644
--- a/graph/cypher/pom.xml
+++ b/graph/cypher/pom.xml
@@ -23,7 +23,7 @@
   <parent>
     <groupId>org.apache.spark</groupId>
     <artifactId>spark-parent_2.12</artifactId>
-    <version>3.0.0-SNAPSHOT</version>
+    <version>3.0.0-preview</version>
     <relativePath>../../pom.xml</relativePath>
   </parent>
 
diff --git a/graph/graph/pom.xml b/graph/graph/pom.xml
index 7438ee5..8ed0b92 100644
--- a/graph/graph/pom.xml
+++ b/graph/graph/pom.xml
@@ -23,7 +23,7 @@
   <parent>
     <groupId>org.apache.spark</groupId>
     <artifactId>spark-parent_2.12</artifactId>
-    <version>3.0.0-SNAPSHOT</version>
+    <version>3.0.0-preview</version>
     <relativePath>../../pom.xml</relativePath>
   </parent>
 
diff --git a/graphx/pom.xml b/graphx/pom.xml
index 444568a..6f46ccc 100644
--- a/graphx/pom.xml
+++ b/graphx/pom.xml
@@ -21,7 +21,7 @@
   <parent>
     <groupId>org.apache.spark</groupId>
     <artifactId>spark-parent_2.12</artifactId>
-    <version>3.0.0-SNAPSHOT</version>
+    <version>3.0.0-preview</version>
     <relativePath>../pom.xml</relativePath>
   </parent>
 
diff --git a/hadoop-cloud/pom.xml b/hadoop-cloud/pom.xml
index 02734e8..7c9357f 100644
--- a/hadoop-cloud/pom.xml
+++ b/hadoop-cloud/pom.xml
@@ -22,7 +22,7 @@
   <parent>
     <groupId>org.apache.spark</groupId>
     <artifactId>spark-parent_2.12</artifactId>
-    <version>3.0.0-SNAPSHOT</version>
+    <version>3.0.0-preview</version>
     <relativePath>../pom.xml</relativePath>
   </parent>
 
diff --git a/launcher/pom.xml b/launcher/pom.xml
index e75e834..86f9c1a 100644
--- a/launcher/pom.xml
+++ b/launcher/pom.xml
@@ -22,7 +22,7 @@
   <parent>
     <groupId>org.apache.spark</groupId>
     <artifactId>spark-parent_2.12</artifactId>
-    <version>3.0.0-SNAPSHOT</version>
+    <version>3.0.0-preview</version>
     <relativePath>../pom.xml</relativePath>
   </parent>
 
diff --git a/mllib-local/pom.xml b/mllib-local/pom.xml
index 2eab868..497b70d 100644
--- a/mllib-local/pom.xml
+++ b/mllib-local/pom.xml
@@ -21,7 +21,7 @@
   <parent>
     <groupId>org.apache.spark</groupId>
     <artifactId>spark-parent_2.12</artifactId>
-    <version>3.0.0-SNAPSHOT</version>
+    <version>3.0.0-preview</version>
     <relativePath>../pom.xml</relativePath>
   </parent>
 
diff --git a/mllib/pom.xml b/mllib/pom.xml
index 11769ef..75ab818 100644
--- a/mllib/pom.xml
+++ b/mllib/pom.xml
@@ -21,7 +21,7 @@
   <parent>
     <groupId>org.apache.spark</groupId>
     <artifactId>spark-parent_2.12</artifactId>
-    <version>3.0.0-SNAPSHOT</version>
+    <version>3.0.0-preview</version>
     <relativePath>../pom.xml</relativePath>
   </parent>
 
diff --git a/pom.xml b/pom.xml
index b5c3479..a10850f 100644
--- a/pom.xml
+++ b/pom.xml
@@ -26,7 +26,7 @@
   </parent>
   <groupId>org.apache.spark</groupId>
   <artifactId>spark-parent_2.12</artifactId>
-  <version>3.0.0-SNAPSHOT</version>
+  <version>3.0.0-preview</version>
   <packaging>pom</packaging>
   <name>Spark Project Parent POM</name>
   <url>http://spark.apache.org/</url>
diff --git a/repl/pom.xml b/repl/pom.xml
index c7de67e..284dc92 100644
--- a/repl/pom.xml
+++ b/repl/pom.xml
@@ -21,7 +21,7 @@
   <parent>
     <groupId>org.apache.spark</groupId>
     <artifactId>spark-parent_2.12</artifactId>
-    <version>3.0.0-SNAPSHOT</version>
+    <version>3.0.0-preview</version>
     <relativePath>../pom.xml</relativePath>
   </parent>
 
diff --git a/resource-managers/kubernetes/core/pom.xml b/resource-managers/kubernetes/core/pom.xml
index 487876b..d4a0733 100644
--- a/resource-managers/kubernetes/core/pom.xml
+++ b/resource-managers/kubernetes/core/pom.xml
@@ -20,7 +20,7 @@
   <parent>
     <groupId>org.apache.spark</groupId>
     <artifactId>spark-parent_2.12</artifactId>
-    <version>3.0.0-SNAPSHOT</version>
+    <version>3.0.0-preview</version>
     <relativePath>../../../pom.xml</relativePath>
   </parent>
 
diff --git a/resource-managers/kubernetes/integration-tests/pom.xml b/resource-managers/kubernetes/integration-tests/pom.xml
index c79caff..038613f 100644
--- a/resource-managers/kubernetes/integration-tests/pom.xml
+++ b/resource-managers/kubernetes/integration-tests/pom.xml
@@ -20,7 +20,7 @@
   <parent>
     <groupId>org.apache.spark</groupId>
     <artifactId>spark-parent_2.12</artifactId>
-    <version>3.0.0-SNAPSHOT</version>
+    <version>3.0.0-preview</version>
     <relativePath>../../../pom.xml</relativePath>
   </parent>
 
diff --git a/resource-managers/mesos/pom.xml b/resource-managers/mesos/pom.xml
index 107ba36..2038ddc 100644
--- a/resource-managers/mesos/pom.xml
+++ b/resource-managers/mesos/pom.xml
@@ -20,7 +20,7 @@
   <parent>
     <groupId>org.apache.spark</groupId>
     <artifactId>spark-parent_2.12</artifactId>
-    <version>3.0.0-SNAPSHOT</version>
+    <version>3.0.0-preview</version>
     <relativePath>../../pom.xml</relativePath>
   </parent>
 
diff --git a/resource-managers/yarn/pom.xml b/resource-managers/yarn/pom.xml
index 0e5df14..15671c1 100644
--- a/resource-managers/yarn/pom.xml
+++ b/resource-managers/yarn/pom.xml
@@ -20,7 +20,7 @@
   <parent>
     <groupId>org.apache.spark</groupId>
     <artifactId>spark-parent_2.12</artifactId>
-    <version>3.0.0-SNAPSHOT</version>
+    <version>3.0.0-preview</version>
     <relativePath>../../pom.xml</relativePath>
   </parent>
 
diff --git a/sql/catalyst/pom.xml b/sql/catalyst/pom.xml
index bcebb22..ad7fe28 100644
--- a/sql/catalyst/pom.xml
+++ b/sql/catalyst/pom.xml
@@ -22,7 +22,7 @@
   <parent>
     <groupId>org.apache.spark</groupId>
     <artifactId>spark-parent_2.12</artifactId>
-    <version>3.0.0-SNAPSHOT</version>
+    <version>3.0.0-preview</version>
     <relativePath>../../pom.xml</relativePath>
   </parent>
 
diff --git a/sql/core/pom.xml b/sql/core/pom.xml
index 3a8b7d2..3565056 100644
--- a/sql/core/pom.xml
+++ b/sql/core/pom.xml
@@ -22,7 +22,7 @@
   <parent>
     <groupId>org.apache.spark</groupId>
     <artifactId>spark-parent_2.12</artifactId>
-    <version>3.0.0-SNAPSHOT</version>
+    <version>3.0.0-preview</version>
     <relativePath>../../pom.xml</relativePath>
   </parent>
 
diff --git a/sql/hive-thriftserver/pom.xml b/sql/hive-thriftserver/pom.xml
index 9dd9270..64b7826 100644
--- a/sql/hive-thriftserver/pom.xml
+++ b/sql/hive-thriftserver/pom.xml
@@ -22,7 +22,7 @@
   <parent>
     <groupId>org.apache.spark</groupId>
     <artifactId>spark-parent_2.12</artifactId>
-    <version>3.0.0-SNAPSHOT</version>
+    <version>3.0.0-preview</version>
     <relativePath>../../pom.xml</relativePath>
   </parent>
 
diff --git a/sql/hive/pom.xml b/sql/hive/pom.xml
index f627227..1f3fbef 100644
--- a/sql/hive/pom.xml
+++ b/sql/hive/pom.xml
@@ -22,7 +22,7 @@
   <parent>
     <groupId>org.apache.spark</groupId>
     <artifactId>spark-parent_2.12</artifactId>
-    <version>3.0.0-SNAPSHOT</version>
+    <version>3.0.0-preview</version>
     <relativePath>../../pom.xml</relativePath>
   </parent>
 
diff --git a/streaming/pom.xml b/streaming/pom.xml
index 87af638..7394391 100644
--- a/streaming/pom.xml
+++ b/streaming/pom.xml
@@ -21,7 +21,7 @@
   <parent>
     <groupId>org.apache.spark</groupId>
     <artifactId>spark-parent_2.12</artifactId>
-    <version>3.0.0-SNAPSHOT</version>
+    <version>3.0.0-preview</version>
     <relativePath>../pom.xml</relativePath>
   </parent>
 
diff --git a/tools/pom.xml b/tools/pom.xml
index e380e86..e260897 100644
--- a/tools/pom.xml
+++ b/tools/pom.xml
@@ -20,7 +20,7 @@
   <parent>
     <groupId>org.apache.spark</groupId>
     <artifactId>spark-parent_2.12</artifactId>
-    <version>3.0.0-SNAPSHOT</version>
+    <version>3.0.0-preview</version>
     <relativePath>../pom.xml</relativePath>
   </parent>