Bump version to 15.10.0

This releases the Silo swap (!1463 (merged)), as asked on that MR. Docker Hub no longer serves minio/minio, so the object-storage end-to-end job in gitlab-org/gitlab fails at the image pull while it pins gitlab-qa 15.9.0. The job recovers once gitlab-org/gitlab takes 15.10.0.

15.10.0 is a minor bump:

• The release notes list one change, the Silo swap, and one removal, the Chaos scenario (!1474 (merged)).
• A scenario removal has shipped in a minor before: Remove suggested reviewers scenario went out in 15.6.0.
• Chaos already failed at 15.9.0. chaos.rb:25 calls run_gitaly_cluster, which only component/gitaly_cluster.rb:65 defines, and nothing in the scenario's class chain includes that component. A search of gitlab-org finds no use of Integration::Chaos.

Diff

15.9.0...b573894b

Pre-merge checklist

• Diff link is up-to-date.
• Check the release notes: https://gitlab.com/api/v4/projects/gitlab-org%2Fgitlab-qa/repository/changelog?version=15.10.0
• Based on the diff and the release notes, version.rb is updated, according to SemVer.

Post-merge checklist

• In the pipeline-common project, update the GITLAB_QA_VERSION (make sure to add a Changelog: trailer to the commit) and create a release.
• Unless already done by renovate-gitlab-bot, in the GitLab project, update the ref for pipeline-common in .gitlab/ci/qa-common/main.gitlab-ci.yml.
• Unless already done by renovate-gitlab-bot, or if you need it sooner, in the GitLab project, update the gitlab-qa gem version in qa/Gemfile and qa/Gemfile.lock (for an example, see: gitlab!117054 (merged)).

An AI coding assistant wrote this change. It ran bundle install with BUNDLE_FROZEN=true, bundle exec rspec and RuboCop on lib/gitlab/qa/version.rb with Ruby 3.3.11 on a local checkout.