[maven-release-plugin] Prepare release [skip ci]

Author: uhafner

pom.xml

@@ -26,7 +26,7 @@
     <connection>scm:git:https://github.com/jenkinsci/analysis-model.git</connection>
     <developerConnection>scm:git:git@github.com:jenkinsci/analysis-model.git</developerConnection>
     <url>https://github.com/jenkinsci/analysis-model</url>
-    <tag>${scmTag}</tag>
+    <tag>v13.21.0</tag>
   </scm>
 
   <licenses>
@@ -54,8 +54,8 @@
   <properties>
     <scmTag>HEAD</scmTag>
     <revision>13.21.0</revision>
-    <changelist>-SNAPSHOT</changelist>
-    <previousVersion>13.20.0</previousVersion>
+    <changelist></changelist>
+    <previousVersion>13.21.0</previousVersion>
 
     <module.name>edu.hm.hafner.analysis.model</module.name>