Test on Ruby 3.4

Author: horgh

.github/workflows/rubocop.yml

@@ -13,6 +13,6 @@ jobs:
       - uses: actions/checkout@v4
       - uses: ruby/setup-ruby@v1
         with:
-          ruby-version: 3.3
+          ruby-version: 3.4
       - run: bundle install
       - run: bundle exec rake -t rubocop

.github/workflows/test.yml

@@ -20,6 +20,7 @@ jobs:
             3.1,
             3.2,
             3.3,
+            3.4,
             jruby,
           ]
         exclude: