Bump actions/checkout from 5 to 6 (#36)

Author: dependabot[bot]

.github/workflows/ci.yml

@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Configure Git Credentials
         run: |
           git config user.name github-actions[bot]