Do not run pipeline on draft merge request

(grafted from e1cc6c69ebd2535cca02303e54b4813b8a4a8cb5)

--HG--
branch : 7.0

.gitlab-ci.yml

@@ -2,6 +2,8 @@ workflow:
   rules:
     - if: $CI_COMMIT_BRANCH =~ /^topic\/.*/ && $CI_PIPELINE_SOURCE == "push"
       when: never
+    - if: $CI_PIPELINE_SOURCE == "merge_request_event" && $CI_MERGE_REQUEST_TITLE =~ /^(\[Draft\]|\(Draft\)|Draft:)/
+      when: never
     - when: always
 
 stages: