Change label `Category:Code Review` to `Category:Code Review Workflow`

Summary

This template is for new or renaming Category labels. This review helps to ensure there will be no impact with triage automation and reports.

Link the merge request to www-gitlab-com for the category.yml change
(If applicable) Label migration on existing issues and merge requests: apply the new label to opened & closed issues, and open & merged merge requests.
(If applicable) Rename the old label by adding [DEPRECATED] at the end of the label name, like ~"CI/CD [DEPRECATED]".