Draft: One-off migration to relabel Category::Projects

What is this label migration for?

One-off migration to relabel ~"Category:Projects [DEPRECATED]" to Category:Groups & Projects.

Target Label	Action
Category:Groups & Projects	Remove label ~"Category:Projects [DEPRECATED]"

After this one-off, we should remove completely the ~"Category:Projects [DEPRECATED]" label.

Related to #1335 (closed) and gitlab-com/www-gitlab-com#14554 (closed).

Expected impact & dry-runs

From the dry-run job, we can see:

• ✅ 20 epics, aligned with expectations. Epic list
• ✅ 183 issues, aligned with expectations. Issues list
• ✅ 51 merge requests, aligned with expectations. Merge requests list

Action items

• Ensure you have read the label migration documentation
• (If applicable) Identify the affected groups and how to communicate to them:
  • /cc @person_or_group =>
  • Relevant Slack channels =>
  • Engineering week-in-review
• Close the MR (Don't Merge!) after migration is done.