Switch from Travis to GitHub Actions (#1978)

.github/workflows/ci.yml

@@ -0,0 +1,21 @@
+name: ci
+on: [push,pull_request]
+jobs:
+  test:
+    name: Node ${{ matrix.node }} / ${{ matrix.os }}
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os:
+          - ubuntu-latest
+        node:
+          - '16'
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-node@v2
+        with:
+          node-version: ${{ matrix.node }}
+      - run: npm install
+      - run: npm run build --if-present
+      - run: npm test