chore(deps): Update actions/checkout action to v6 (#43)

Author: cq-bot

.github/workflows/ci.yml

@@ -14,7 +14,7 @@ jobs:
         python-version: ["3.11"]
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@v6