Merge branch 'allow-merge-train-skip' into 'master'

Allow skipping of Merge Train syncs

See merge request gitlab-org/gitlab!46780

.gitlab/ci/rules.gitlab-ci.yml

@@ -676,10 +676,14 @@
 ##################
 .releases:rules:canonical-dot-com-gitlab-stable-branch-only:
   rules:
+    - if: '$CI_COMMIT_MESSAGE =~ /\[merge-train skip\]/'
+      when: never
     - if: '$CI_SERVER_HOST == "gitlab.com" && $CI_PROJECT_PATH == "gitlab-org/gitlab" && $CI_COMMIT_REF_NAME =~ /^[\d-]+-stable-ee$/'
 
 .releases:rules:canonical-dot-com-security-gitlab-stable-branch-only:
   rules:
+    - if: '$CI_COMMIT_MESSAGE =~ /\[merge-train skip\]/'
+      when: never
     - if: '$CI_SERVER_HOST == "gitlab.com" && $CI_PROJECT_PATH == "gitlab-org/security/gitlab" && $CI_COMMIT_REF_NAME =~ /^[\d-]+-stable-ee$/'
 
 #################