[maven-release-plugin] prepare release 2.3.1

pom.xml

@@ -5,7 +5,7 @@
 
     <groupId>com.englishtown</groupId>
     <artifactId>stash-hook-mirror</artifactId>
-    <version>2.4.0-SNAPSHOT</version>
+    <version>2.3.1</version>
 
     <organization>
         <name>Englishtown</name>
@@ -131,7 +131,7 @@
         <connection>scm:git:git@github.com:ef-labs/stash-hook-mirror.git</connection>
         <developerConnection>scm:git:git@github.com:ef-labs/stash-hook-mirror.git</developerConnection>
         <url>https://github.com/ef-labs/stash-hook-mirror</url>
-        <tag>HEAD</tag>
+        <tag>2.3.1</tag>
     </scm>
 
     <distributionManagement>