[maven-release-plugin] prepare release 0.21.0-alpha2

pom.xml

@@ -1,14 +1,12 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-  xmlns="http://maven.apache.org/POM/4.0.0"
-  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
 
   <modelVersion>4.0.0</modelVersion>
   <name>Zeebe Test Container</name>
   <artifactId>zeebe-test-container</artifactId>
   <packaging>jar</packaging>
   <groupId>io.zeebe</groupId>
-  <version>0.21.0-SNAPSHOT</version>
+  <version>0.21.0-alpha2</version>
   <inceptionYear>2019</inceptionYear>
   <url>https://github.com/zeebe-io/zeebe-test-container</url>
 
@@ -17,7 +15,7 @@
     <artifactId>camunda-release-parent</artifactId>
     <version>2.5</version>
     <!-- do not remove empty tag - http://jira.codehaus.org/browse/MNG-4687 -->
-    <relativePath/>
+    <relativePath />
   </parent>
 
   <properties>
@@ -313,6 +311,6 @@
     <connection>scm:git:git@github.com:zeebe-io/zeebe-test-container.git</connection>
     <developerConnection>scm:git:git@github.com:zeebe-io/zeebe-test-container.git
     </developerConnection>
-    <tag>HEAD</tag>
+    <tag>0.21.0-alpha2</tag>
   </scm>
 </project>