Merge branch 'match-any-stable-branch-ee' into 'master'

EE: Consider we might have prefix for stable branches

See merge request gitlab-org/gitlab-ee!5900

.gitlab-ci.yml

@@ -454,7 +454,7 @@ retrieve-tests-metadata:
     - //@gitlab-org/gitlab-ee
   except:
     - master
-    - /^[\d-]+-stable(-ee)?$/
+    - /[\d-]+-stable(-ee)?/
     - /\bce\-to\-ee\b/
     - /(^docs[\/-].*|.*-docs$)/