Merge branch 'add-allowance-for-feature-flag-after-ff' into 'master'

Add allowance to merge feature flags MRs

See merge request gitlab-org/gitlab-ce!22267

PROCESS.md

@@ -208,6 +208,7 @@ the stable branch are:
 * Fixes or improvements to automated QA scenarios
 * [Documentation updates](https://docs.gitlab.com/ee/development/documentation/workflow.html#documentation-shipped-late) for changes in the same release
 * New or updated translations (as long as they do not touch application code)
+* Changes that are behind a feature flag and have the ~"feature flag" label
 
 During the feature freeze all merge requests that are meant to go into the
 upcoming release should have the correct milestone assigned _and_ the