Full refresh of Gemfile.lock and yarn.lock

What does this MR do and why?

Mostly to progress: !3664 (merged), fully refresh Gemfile.lock and yarn.lock because the usual automated process is very conservative about version bumps, and we want to take advantage of some new versions of dependencies.

In particular, this moves us from rack 2.x to 3.0.x.

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

1. Configure a local GitLab Docs environment: https://gitlab.com/gitlab-org/gitlab-docs/-/blob/main/doc/setup.md.
2. Run make setup.
3. Run make view and confirm everything looks ok.

Merge request acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this merge request.