Bump ruby/setup-ruby from 1.243.0 to 1.255.0

Bumps [ruby/setup-ruby](https://github.com/ruby/setup-ruby) from 1.243.0 to 1.255.0.
- [Release notes](https://github.com/ruby/setup-ruby/releases)
- [Changelog](https://github.com/ruby/setup-ruby/blob/master/release.rb)
- [Commits](ruby/setup-ruby@v1.243.0...v1.255.0)

---
updated-dependencies:
- dependency-name: ruby/setup-ruby
  dependency-version: 1.255.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

.github/workflows/jekyll.yml

@@ -19,7 +19,7 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v5
       - name: Setup Ruby
-        uses: ruby/setup-ruby@v1.243.0
+        uses: ruby/setup-ruby@v1.255.0
         with:
           ruby-version: '3.1'
       - name: Setup Emacs