Update actions/checkout action to v6

Author: renovate-bot

.github/workflows/release.yaml

@@ -13,7 +13,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout code
-        uses: actions/checkout@v4.2.2
+        uses: actions/checkout@v6.0.0
 
       - name: Prepare .spoon directory for zipping
         run: |