Update checkout to v6

Author: tpwo

.github/workflows/pre-commit.yml

@@ -13,5 +13,5 @@ jobs:
   pre-commit:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
     - uses: tox-dev/action-pre-commit-uv@v1