ci: gh actions: update

.github/workflows/ruby.yml

@@ -0,0 +1,29 @@
+name: Ruby CI
+on: [push, pull_request]
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        ruby: ['2.5', '2.6', '2.7', 'jruby-head', 'ruby-head']
+        gemfile: ['Gemfile']
+        exclude:
+          - ruby: 2.7
+            gemfile: activesupport-4.2.x
+          - ruby: ruby-head
+            gemfile: activesupport-4.2.x
+          - ruby: jruby-head
+            gemfile: activesupport-4.2.x
+    env:
+      BUNDLE_GEMFILE: ${{ matrix.gemfile }}
+    name: Ruby ${{ matrix.ruby }} with ${{ matrix.gemfile }}
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up Ruby
+      uses: ruby/setup-ruby@v1
+      with:
+        ruby-version: ${{ matrix.ruby }}
+        bundler-cache: true
+    - name: Run tests
+      run: bundle exec rake