chore: switch CI to github actions

Author: broofa

.github/workflows/ci.yml

@@ -0,0 +1,26 @@
+name: Node.js CI
+
+on:
+  push:
+    branches: [ $default-branch ]
+  pull_request:
+    branches: [ $default-branch ]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        node-version: [8.x, 10.x, 12.x, 14.x]
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: Use Node.js ${{ matrix.node-version }}
+      uses: actions/setup-node@v1
+      with:
+        node-version: ${{ matrix.node-version }}
+    - run: npm ci
+    - run: npm run build --if-present
+    - run: npm test