update to GORM 6 release

Author: graemerocher

build.gradle

@@ -33,7 +33,7 @@ ext {
     commonsCollectionsVersion = "3.2.1"
     commonsIOVersion = "2.2"
     commonsLangVersion = "2.6"
-    datastoreVersion = "6.0.0.RC2"
+    datastoreVersion = "6.0.0.RELEASE"
     gantVersion = "1.9.6"
     gdocEngineVersion = "1.0.1"
     groovyVersion = System.getenv('CI_GROOVY_VERSION') ?: "2.4.7"