Add a workflow to verify Prettier formatting

.github/workflows/check-formatting.yml

@@ -0,0 +1,26 @@
+name: Checking formatting
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+
+      - name: Setup Node.JS
+        uses: actions/setup-node@v3
+        with:
+          node-version: 16.x
+          cache: 'npm'
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Verify formatting
+        run: npm run format:check