Bump API version to released 2.9

Change-Id: Ia1da3fcc6a53684dc2596348a7dd9e2a962b9ad2
Signed-off-by: Edwin Kempin <edwin.kempin@sap.com>

pom.xml

diff --git a/pom.xml b/pom.xml
index 92da033..1a7588a 100644
--- a/pom.xml
+++ b/pom.xml
@@ -10,7 +10,7 @@
   <properties>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     <Gerrit-ApiType>PLUGIN</Gerrit-ApiType>
-    <Gerrit-ApiVersion>2.9-SNAPSHOT</Gerrit-ApiVersion>
+    <Gerrit-ApiVersion>2.9</Gerrit-ApiVersion>
   </properties>
 
   <build>