Update ruby/setup-ruby action to v1.278.0 (#239)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/pages.yml

@@ -33,7 +33,7 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v4
       - name: Setup Ruby
-        uses: ruby/setup-ruby@v1.277.0
+        uses: ruby/setup-ruby@v1.278.0
         with:
           ruby-version: '3.4.8' # Not needed with a .ruby-version file
           bundler-cache: true # runs 'bundle install' and caches installed gems automatically