Add Ruby 3.3 and run Rubocop on last Ruby version only

Author: JuanVqz

.github/workflows/main.yml

@@ -9,7 +9,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu]
-        ruby-version: ["2.6", "2.7", "3.0", "3.1", "3.2"]
+        ruby-version: ["2.6", "2.7", "3.0", "3.1", "3.2", "3.3"]
     steps:
       - uses: actions/checkout@v2
       - name: Setup Ruby ${{ matrix.ruby-version }}
@@ -22,3 +22,8 @@ jobs:
           gem install bundler -v 2.4.6
           bundle install --jobs 4 --retry 3
           bundle exec rake
+      - name: Run RuboCop on latest Ruby
+        if: matrix.ruby-version == '3.3'
+        run: |
+          gem install rubocop
+          rubocop --parallel --config .rubocop.yml