Provide GitHub Action to build extension on master branch update and

.github/workflows/build.yaml

@@ -0,0 +1,26 @@
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+  workflow_dispatch:
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+    - uses: actions/setup-node@v2
+      with:
+        node-version: '16'
+        cache: 'npm'
+    - name: Install global dependencies
+      run: npm install -g typescript vsce
+    - name: npm-ci
+      run: npm ci
+    - name: npm-compile
+      run: npm run compile
+    - name: vsce package
+      run: vsce package