Use bundler cache

Author: yujideveloper

.github/workflows/ruby.yml

@@ -14,7 +14,6 @@ jobs:
       uses: ruby/setup-ruby@v1
       with:
         ruby-version: ${{ matrix.ruby }}
-    - name: Install dependencies
-      run: bundle install
+        bundler-cache: true
     - name: Run tests
       run: bundle exec rake spec