ci: add formatting check

.github/workflows/ci.yml

@@ -11,6 +11,24 @@ on:
       - "**"
 
 jobs:
+  common_checks:
+    name: Common checks
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: 20.8.0
+          cache: 'npm'
+          cache-dependency-path: '**/package-lock.json'
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Check formatting
+        run: npm run format:check
   build_ilc:
     name: Build ILC
     runs-on: ubuntu-latest