Set up a CI build

Author: pimterry

.github/workflows/ci.yml

@@ -0,0 +1,24 @@
+name: CI
+on: push
+jobs:
+  build:
+    name: Build & test
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        node-version: [10.x, 12.x, v14.6.0, 14.x, '*']
+
+    steps:
+      - uses: actions/checkout@v2
+
+      - uses: actions/setup-node@v1
+        with:
+          node-version: ${{ matrix.node-version }}
+
+      - uses: actions-rs/toolchain@v1
+        with:
+          toolchain: stable
+
+      - run: npm install --no-package-lock
+      - run: npm test