feat(CI): use setup-ruby's bundle installer and cache (#275)

Co-authored-by: Joseph Yi <[email protected]>

Author: josephyi

.github/workflows/test.yml

@@ -14,10 +14,12 @@ jobs:
       - uses: ruby/setup-ruby@v1
         with:
           ruby-version: ${{ matrix.ruby_version }}
-      - run: "bundle install"
+          bundler-cache: true
       - run: "bundle exec rake"
   test-with-active-support:
     runs-on: "ubuntu-latest"
+    env:
+      BUNDLE_GEMFILE: active-support.gemfile
     strategy:
       fail-fast: false
       matrix:
@@ -27,9 +29,5 @@ jobs:
       - uses: ruby/setup-ruby@v1
         with:
           ruby-version: ${{ matrix.ruby_version }}
-      - run: "bundle install "
-        env:
-          BUNDLE_GEMFILE: active-support.gemfile
+          bundler-cache: true
       - run: "bundle exec rake spec_with_active_support"
-        env:
-          BUNDLE_GEMFILE: active-support.gemfile