Update version to 7.29.0

• Diff: https://gitlab.com/gitlab-org/gitlab-qa/compare/v7.28.0...882965bfce8c6de07fcfc6001872665d99b95c7a

Release notes:

Other changes (CI, backstage)

• Restart GitLab in Decomposition scenario and re... (!957 - merged)
• Add ability to configure log path (!961 - merged)

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.