Update GitLab Bot to warn MR author to create EE MR upon library updates
Summary
When we perform frontend library upgrade in CE and update frontend files with related changes, it is easy to miss creating EE MR and do similar changes in EE-only frontend files. Same thing happened when https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/22632 was created without having corresponding EE MR, leading to that day's CE to EE MR https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/8139 fail with compilation errors.
Proposal
We already utilize @gitlab-bot for several static analysis tasks where CI cannot do the job (or is an overkill to have a CI job). A simple fix for this would be to check MR diff for yarn.lock
/package.json
file updates in CE MR and show a warning to create EE MR with cherry-picked commits from CE (and may be also have branch naming convention to match with that of ee_compat_check
).