Revert "[maven-release-plugin] prepare release 0.5.0"

This reverts commit 186df0c36981a308338792f02d93fc59776b0b7c.
diff --git a/commons-rdf-api/pom.xml b/commons-rdf-api/pom.xml
index 203eacb..f6e0eed 100644
--- a/commons-rdf-api/pom.xml
+++ b/commons-rdf-api/pom.xml
@@ -24,7 +24,7 @@
     <parent>
         <groupId>org.apache.commons</groupId>
         <artifactId>commons-rdf-parent</artifactId>
-        <version>0.5.0</version>
+        <version>0.5.0-SNAPSHOT</version>
     </parent>
 
     <artifactId>commons-rdf-api</artifactId>
diff --git a/commons-rdf-integration-tests/pom.xml b/commons-rdf-integration-tests/pom.xml
index afe6b76..7d9c44c 100644
--- a/commons-rdf-integration-tests/pom.xml
+++ b/commons-rdf-integration-tests/pom.xml
@@ -23,7 +23,7 @@
 	<parent>
 		<groupId>org.apache.commons</groupId>
 		<artifactId>commons-rdf-parent</artifactId>
-		<version>0.5.0</version>
+		<version>0.5.0-SNAPSHOT</version>
 	</parent>
 	<artifactId>commons-rdf-integration-tests</artifactId>
 	<name>Commons RDF Integration tests</name>
diff --git a/commons-rdf-jena/pom.xml b/commons-rdf-jena/pom.xml
index 6c6e592..c518cdf 100644
--- a/commons-rdf-jena/pom.xml
+++ b/commons-rdf-jena/pom.xml
@@ -24,7 +24,7 @@
 	<parent>
 		<groupId>org.apache.commons</groupId>
 		<artifactId>commons-rdf-parent</artifactId>
-		<version>0.5.0</version>
+		<version>0.5.0-SNAPSHOT</version>
 	</parent>
 
 	<artifactId>commons-rdf-jena</artifactId>
diff --git a/commons-rdf-jsonld-java/pom.xml b/commons-rdf-jsonld-java/pom.xml
index 674c65b..5dac9d4 100644
--- a/commons-rdf-jsonld-java/pom.xml
+++ b/commons-rdf-jsonld-java/pom.xml
@@ -24,7 +24,7 @@
     <parent>
         <groupId>org.apache.commons</groupId>
         <artifactId>commons-rdf-parent</artifactId>
-        <version>0.5.0</version>
+        <version>0.5.0-SNAPSHOT</version>
     </parent>
 
     <artifactId>commons-rdf-jsonld-java</artifactId>
diff --git a/commons-rdf-rdf4j/pom.xml b/commons-rdf-rdf4j/pom.xml
index 39ca88d..2f9ddc3 100644
--- a/commons-rdf-rdf4j/pom.xml
+++ b/commons-rdf-rdf4j/pom.xml
@@ -24,7 +24,7 @@
 	<parent>
 		<groupId>org.apache.commons</groupId>
 		<artifactId>commons-rdf-parent</artifactId>
-		<version>0.5.0</version>
+		<version>0.5.0-SNAPSHOT</version>
 	</parent>
 
 	<artifactId>commons-rdf-rdf4j</artifactId>
diff --git a/commons-rdf-simple/pom.xml b/commons-rdf-simple/pom.xml
index d9b3642..1438f07 100644
--- a/commons-rdf-simple/pom.xml
+++ b/commons-rdf-simple/pom.xml
@@ -24,7 +24,7 @@
     <parent>
         <groupId>org.apache.commons</groupId>
         <artifactId>commons-rdf-parent</artifactId>
-        <version>0.5.0</version>
+        <version>0.5.0-SNAPSHOT</version>
     </parent>
 
     <artifactId>commons-rdf-simple</artifactId>
diff --git a/pom.xml b/pom.xml
index 9189221..e9722e4 100644
--- a/pom.xml
+++ b/pom.xml
@@ -28,7 +28,7 @@
     </parent>
 
     <artifactId>commons-rdf-parent</artifactId>
-    <version>0.5.0</version>
+    <version>0.5.0-SNAPSHOT</version>
     <packaging>pom</packaging>
 
     <name>Commons RDF</name>
@@ -79,7 +79,7 @@
         <url>https://git-wip-us.apache.org/repos/asf/commons-rdf.git</url>
         <connection>scm:git:https://git-wip-us.apache.org/repos/asf/commons-rdf.git</connection>
         <developerConnection>scm:git:https://git-wip-us.apache.org/repos/asf/commons-rdf.git</developerConnection>
-        <tag>0.5.0</tag>
+        <tag>HEAD</tag>
     </scm>
 
     <issueManagement>