Merge pull request #7 from ruby/use-bundler-cache

CI: use bundler-cache: true, add Ruby 3.1 to build matrix

Author: hsbt

.github/workflows/test.yml

@@ -7,7 +7,7 @@ jobs:
     name: build (${{ matrix.ruby }} / ${{ matrix.os }})
     strategy:
       matrix:
-        ruby: [ head, '3.0', '2.7', '2.6' ]
+        ruby: [ head, '3.1', '3.0', '2.7', '2.6' ]
         os: [ ubuntu-latest, macos-latest ]
     runs-on: ${{ matrix.os }}
     steps:
@@ -16,7 +16,6 @@ jobs:
       uses: ruby/setup-ruby@v1
       with:
         ruby-version: ${{ matrix.ruby }}
-    - name: Install dependencies
-      run: bundle install
+        bundler-cache: true # 'bundle install' and cache gems
     - name: Run test
-      run: rake test
+      run: bundle exec rake test