Bump ruby/setup-ruby from 1.276.0 to 1.279.0

Bumps [ruby/setup-ruby](https://github.com/ruby/setup-ruby) from 1.276.0 to 1.279.0.
- [Release notes](https://github.com/ruby/setup-ruby/releases)
- [Changelog](https://github.com/ruby/setup-ruby/blob/master/release.rb)
- [Commits](ruby/setup-ruby@ae195bb...b90be12)

---
updated-dependencies:
- dependency-name: ruby/setup-ruby
  dependency-version: 1.279.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.github/workflows/ci.yml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
-    - uses: ruby/setup-ruby@ae195bbe749a7cef685ac729197124a48305c1cb # v1.276.0
+    - uses: ruby/setup-ruby@b90be12699fdfcbee4440c2bba85f6f460446bb0 # v1.279.0
       with:
         bundler-cache: true
     - run: GOVUK_DOCKER_DIR=. make test-ci