Build with plugin API version 2.12

Change-Id: I8b88a64d133d4d394dcf8664618832a5d81d1dfa

pom.xml

diff --git a/pom.xml b/pom.xml
index 4678aed..80b219d 100644
--- a/pom.xml
+++ b/pom.xml
@@ -6,7 +6,7 @@
   <packaging>jar</packaging>
   <name>Gerrit Code Review - Audit Listener SL4J Plugin</name>
   <url>http://maven.apache.org</url>
-  <version>2.11.7</version>
+  <version>2.12</version>
 
   <build>
     <plugins>