add gh workflow to check for prettier formatting

.github/workflows/prettier.yaml

@@ -0,0 +1,34 @@
+name: Prettier
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - main
+
+jobs:
+  ci:
+    runs-on: ${{ matrix.os }}
+
+    strategy:
+      matrix:
+        os: [ubuntu-latest]
+        node: [18.x]
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup node env
+        uses: actions/setup-node@v3
+        with:
+          node-version: ${{ matrix.node }}
+          cache: "npm"
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Check prettier formatting
+        run: npm run format-check