Bump version to 7.2.0

• Diff: https://gitlab.com/gitlab-org/gitlab-qa/compare/v7.1.1...f2f9ba3f60db054fbf1be3a27ae91c175f08fe76

• Release notes:

### New scenarios and scenario updates

- !698 Add omnibus config for license mode

### Other changes (CI, backstage)

- !697 Increase number of parallel ee:update jobs
- !689 Remove ObjectStorage and Packages reference from qa.rb
- !664 Update docker daemon from 19.03 to 20.10.5
- !667 Update Ruby from 2.6 to 3.0 on notify in CI
- !696 Remove testcase issue link from session

• 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.