Stricter version referencing for actions/checkout

Author: porhkz

.github/workflows/s3-deploy.yml

@@ -42,7 +42,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@latest
+        uses: actions/checkout@v4
 
       - name: Configure AWS creds
         uses: aws-actions/configure-aws-credentials@latest