add github actions

.github/workflows/ci.yml

@@ -0,0 +1,47 @@
+name: Extension Actions
+
+on:
+  push:
+    branches: [master]
+  pull_request:
+    branches: [master]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        node-version: [14.x, 16.x]
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v2
+        with:
+          node-version: ${{ matrix.node-version }}
+
+      - name: Cache Node.js modules
+        uses: actions/cache@v2
+        with:
+          path: ~/.npm
+          key: ${{ runner.os }}-node-${{ matrix.node-version }}-${{ hashFiles('**/package-lock.json') }}
+          restore-keys: |
+            ${{ runner.os }}-node-${{ matrix.node-version }}-
+
+      - name: Install dependencies
+        run: npm install
+
+      - name: Compile
+        run: npm run compile
+
+      - name: Run lint
+        run: npm run lint
+
+      - name: Run tests
+        run: npm test
+
+      - name: Run coverage
+        run: npm run coverage