Trigger OMEC docker-publish jobs on Github PR merge

Change-Id: I4cf494521b6c86457ccddd82e24740ab9435d1b6
diff --git a/jjb/docker-publish-github.yaml b/jjb/docker-publish-github.yaml
index 1071aea..148c228 100644
--- a/jjb/docker-publish-github.yaml
+++ b/jjb/docker-publish-github.yaml
@@ -16,7 +16,8 @@
           display-status: 'docker-publish'
 
     triggers:
-      - github
+      - cord-infra-github-pr-trigger-merge:
+          project: '{project}'
 
     wrappers:
       - lf-infra-wrappers: