Merge branch 'renovate-gems/testing-gems' into 'master'

Update dependency gitlab_quality-test_tooling to '~> 1.15.0'

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/144246



Merged-by: Peter Leitzen <pleitzen@gitlab.com>
Approved-by: Peter Leitzen <pleitzen@gitlab.com>
Co-authored-by: GitLab Renovate Bot <gitlab-bot@gitlab.com>