[EE] Automatically update MR merge-ref along merge status
What does this MR do?
Ports https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/28513
Does this MR meet the acceptance criteria?
Conformity
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Changelog entry -
Documentation created/updated or follow-up review issue created -
Code review guidelines -
Merge request performance guidelines -
Style guides -
Database guides -
Separation of EE specific content
Performance and testing
Edited by Oswaldo Ferreira