Merge pull request #13 from ashtanko/renovate/actions-checkout-4.x

Update actions/checkout action to v4

Author: ashtanko

.github/workflows/ci.yml

@@ -16,7 +16,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Setup Flutter
         uses: subosito/flutter-action@v2