Updating ruby

According to the most recent updates, ruby is required to be version 3.3.5, so indicating so in the build file.

Relevant links:
gihub runner-images issue: actions/runner-images#10636
one of the failed runs: https://github.com/cmu-soda/cmu-soda.github.io/actions/runs/12998778012

.github/workflows/jekyll.yml

@@ -36,7 +36,7 @@ jobs:
       - name: Setup Ruby
         uses: ruby/setup-ruby@8575951200e472d5f2d95c625da0c7bec8217c42 # v1.161.0
         with:
-          ruby-version: '3.1' # Not needed with a .ruby-version file
+          ruby-version: '3.3.5' # Not needed with a .ruby-version file
           bundler-cache: true # runs 'bundle install' and caches installed gems automatically
           cache-version: 0 # Increment this number if you need to re-download cached gems
       - name: Setup Pages