Merge pull request #25 from koic/enable_rubocop_on_ci

Enable RuboCop on CI

.github/workflows/ci.yml

@@ -22,3 +22,14 @@ jobs:
         run: bundle install
       - run: bundle exec rake test
         continue-on-error: ${{ matrix.entry.allowed-failure }}
+
+  rubocop:
+    runs-on: ubuntu-latest
+    name: RuboCop
+    steps:
+      - uses: actions/checkout@v3
+      - uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: 3.2 # Specify the oldest supported Ruby version.
+          bundler-cache: true
+      - run: bundle exec rake rubocop