prepare for 5.3.1 release

git-svn-id: https://svn.apache.org/repos/asf/tapestry/tapestry5/branches/5.3@1213787 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/build.gradle b/build.gradle
index 7849548..db562b8 100644
--- a/build.gradle
+++ b/build.gradle
@@ -2,7 +2,7 @@
 
 // Remember that when generating a release, this should be incremented. Also don't forget to
 // tag the release in Subversion.
-tapestryVersion = "5.3.1-rc1"
+tapestryVersion = "5.3.1"
 
 jettyVersion = '7.0.0.v20091005'
 tomcatVersion = '6.0.30'