Removed Grails3 branch from build branch list in travis

Grails3 branch is no longer

Author: nickdos

.travis.yml

@@ -6,8 +6,6 @@ branches:
   only:
     - master
     - hotfix
-    - Grails3
-  
 before_cache:
   - rm -f  $HOME/.gradle/caches/modules-2/modules-2.lock
   - rm -fr $HOME/.gradle/caches/*/plugin-resolution/