Bump version to 7.16.1

• Diff: v7.16.0...8efab59b

• Release notes:

### Other changes (CI, backstage)

- !808 Update reporting script to handle undefined testcase links.

• Checklist before merging:

  • Diff link is up-to-date.
  • Based on the diff, lib/gitlab/qa/version.rb is updated, according to SemVer.
  • Release notes are accurate.

• Checklist after merging:

  • Update the release notes for the newly created tag.