Add back the CI job that makes sure deprecations doc is in sync
What does this MR do and why?
This MR "reverts the revert": !70707 (merged)
Related to #340985 (moved) (step 2)
We originally had a CI job that made sure the deprecations YAML files and the deprecations doc were always in sync. This is very similar to the translations and the gettext:regenerate script. We removed it due to some early struggles, but now it's important to get the job back in as things are getting out of sync and causing confusion.
The job rules detect when the YAML files have been changed, and runs the gitlab:docs:check_deprecations task to see if the doc is up to date. If not, it fails with this message:
$ bin/rake gitlab:docs:check_deprecations
##########
#
# Deprecations doc is outdated! You (or your technical writer) can update it by running `bin/rake gitlab:docs:compile_deprecations`.
#
##########If everything is in sync, then it passes, and the MR can be merged.
Example run of new pipeline job
Example successful job from this MR: https://gitlab.com/gitlab-org/gitlab/-/jobs/1767811137
Related MRs:
In both these MRs, the deprecations were updated, but the script was not run. The next person that ran the script saw extra unexpected changes as a result and it was very confusing:
- YAML file added, but doc not updated: !73530 (diffs)
- Doc updated directly, without updating the YAML file: !72892 (comment 716514340)