switch to gh actions

Author: tycooon

.github/workflows/ci.yml

@@ -0,0 +1,24 @@
+name: CI
+
+on: [push, pull_request]
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+
+    strategy:
+      fail-fast: false
+      matrix:
+        ruby: ["2.5", "2.6", "2.7", "3.0"]
+
+    name: ${{ matrix.ruby }}
+
+    steps:
+    - uses: actions/checkout@v2
+
+    - uses: ruby/setup-ruby@v1
+      with:
+        ruby-version: ${{ matrix.ruby }}
+        bundler-cache: true
+
+    - run: bundle exec rake