Bump version to 5.17.0

• Diff: https://gitlab.com/gitlab-org/gitlab-qa/compare/v5.16.0...93b01a6397ab4b3ef60e6378a4b2c235a1446b62

• Release notes:

### Doc changes

- !493 Add Geo instance and staging scenarios to doc.
- !497 Note how env vars are documented.

### Other changes (CI, backstage)

- !496 Add ability to run specs multiple times with different feature flags.

• 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:

  • Create a tag for the new release version.