Update POM version info for 2.1 examples branch

Update the 2.1 version of the accumulo-examples POM file

* Set the accumulo-examples project version to `2.1.0`.
* Update the `accumulo.version` property to `2.1.0` 

This branch of the accumulo-examples project should be targeted to work against any version of the Accumulo 2.1.x line of development.
diff --git a/pom.xml b/pom.xml
index 1384798..7fbec6a 100644
--- a/pom.xml
+++ b/pom.xml
@@ -24,11 +24,11 @@
   </parent>
   <groupId>org.apache.accumulo</groupId>
   <artifactId>accumulo-examples</artifactId>
-  <version>2.1.1-SNAPSHOT</version>
+  <version>2.1.0</version>
   <name>Apache Accumulo Examples</name>
   <description>Example code and corresponding documentation for using Apache Accumulo</description>
   <properties>
-    <accumulo.version>2.1.1-SNAPSHOT</accumulo.version>
+    <accumulo.version>2.1.0</accumulo.version>
     <eclipseFormatterStyle>contrib/Eclipse-Accumulo-Codestyle.xml</eclipseFormatterStyle>
     <hadoop.version>3.3.4</hadoop.version>
     <maven.compiler.release>11</maven.compiler.release>