ubuntu-latest pipelines will use ubuntu-24.04 soon. For more details, see https://github.com/actions/runner-images/issues/10636

The github-pages gem can't satisfy your Gemfile's dependencies. If you want to use a different Jekyll version or need additional dependencies, consider building Jekyll site with GitHub Actions: https://jekyllrb.com/docs/continuous-integration/github-actions/