Improve GithubActions settings

.github/workflows/ci.yml

@@ -29,6 +29,9 @@ jobs:
           - rails_7.0.8
           - rails_6.1.7
 
+    env: # $BUNDLE_GEMFILE must be set at the job level, so it is set for all steps
+      BUNDLE_GEMFILE: ${{ github.workspace }}/gemfiles/${{ matrix.rails }}.gemfile
+
     steps:
       - name: Checkout
         uses: actions/checkout@v4
@@ -37,21 +40,11 @@ jobs:
         uses: ruby/setup-ruby@v1
         with:
           ruby-version: ${{ matrix.ruby }}
-
-      - name: Bundle
-        env:
-          RAILS_VERSION: ${{ matrix.rails }}
-          BUNDLE_GEMFILE: gemfiles/${{ matrix.rails }}.gemfile
-        run: |
-          gem install bundler
-          bundle config path vendor/bundle
-          bundle install --jobs 4 --retry 3
+          bundler-cache: true
 
       - name: RSpec & publish code coverage
         uses: paambaati/[email protected]
         env:
-          RAILS_VERSION: ${{ matrix.rails }}
-          BUNDLE_GEMFILE: gemfiles/${{ matrix.rails }}.gemfile
           CC_TEST_REPORTER_ID: ${{ secrets.CC_TEST_REPORTER_ID }}
         with:
           coverageCommand: bin/rake