Bump version 7.12.0

• Diff: https://gitlab.com/gitlab-org/gitlab-qa/compare/da3f22f308694c7222ad54a727df840b71653ab3...ac3292f52225b1018166794a14c88b5f3033f2ef

• Release notes:

### New scenarios and scenario updates

- !773 Refactors existing Registry TLS scenario
- !773 Adds a no TLS Registry scenario
- !773 Adds a configuration for Registry object storage

### Fixes

- !774 Updates gitaly cluster to use a shorter automatic reconciliation duration


### Other changes (CI, backstage)

- !773 Adds Registry with Object Storage job. 

• 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.