Update actions/checkout action to v6

Author: renovate[bot]

.github/workflows/lint.yml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v1
+    - uses: actions/checkout@v6
     - name: Set up Python 3.11
       uses: actions/setup-python@v1
       with: