Update actions/checkout action to v6

Author: renovate[bot]

.github/workflows/github-release.yml

@@ -10,7 +10,7 @@ jobs:
     name: Create Release
     runs-on: ubuntu-20.04
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v6
       - name: Create Release
         id: create_release
         uses: actions/create-release@v1