Add release extension

Author: dantleech

.github/workflows/release.yml

@@ -0,0 +1,26 @@
+on:
+  release:
+    types:
+      - created
+
+name: Upload the extension
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - name: Checkout
+      uses: actions/checkout@v2
+    - name: Install Node.js
+      uses: actions/setup-node@v2
+      with:
+        node-version: 14
+    - run: mkdir artifacts
+    - run: npm install
+    - run: npm build
+    - name: "Release Extension"
+      uses: actions/upload-release-asset@v1
+      with:
+        upload_url: ${{ github.event.release.upload_url }}
+        asset_path: ./artifacts/phpactor.vsix
+        asset_name: phpactor.vsix
+        asset_content_type: application/octet-stream