Update ruby.yml

.github/workflows/ruby.yml

@@ -13,8 +13,17 @@ jobs:
       uses: actions/setup-ruby@v1
       with:
         ruby-version: 2.6.x
+    - name: Cache gems
+      uses: actions/cache@v1
+      with:
+        path: vendor/bundle
+        key: ${{ runner.os }}-gem-${{ hashFiles('**/Gemfile.lock') }}
+        restore-keys: |
+          ${{ runner.os }}-gem-
     - name: Build and test with Rake
       run: |
         gem install bundler
+        bundle config force_ruby_platform true
+        bundle config path vendor/bundle
         bundle install --jobs 4 --retry 3
         bundle exec rake