test with GitHub Actions

Signed-off-by: Robb Kidd <[email protected]>

.github/workflows/ci.yml

@@ -0,0 +1,27 @@
+name: CI
+on:
+  push:
+    branches:
+    - master
+  pull_request:
+    branches:
+    - master
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        ruby: [ '2.4', '2.5', '2.6', '2.7' ]
+    name: Lint & Test with Ruby ${{ matrix.ruby }}
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-ruby@v1
+        with:
+          ruby-version: ${{ matrix.ruby }}
+      - name: Setup Ruby environment
+        run: |
+          gem install bundler
+          bundle install --jobs 4 --retry 3
+      - name: Testing & Linting
+        run: bundle exec rake