Update GITLAB_PAGES_VERSION

- Update Feature Flag.md issue template label to group::knowledge
- In v16.8.0, fix pages auth when namespace-in-path is enabled
- Terminate connection on 429 on the HTTP rate-limiter

Reference: https://gitlab.com/gitlab-org/gitlab-pages/-/compare/d8501186fd12f2d17ee48fa27a63488f58b0d0be...8a5598bb7b9a2d5a57a299ffda88a71adc57f41b?from_project_id=734943&straight=false

Changelog: changed

GITLAB_PAGES_VERSION

-d8501186fd12f2d17ee48fa27a63488f58b0d0be
+8a5598bb7b9a2d5a57a299ffda88a71adc57f41b