Bump actions/checkout from 4 to 6

Bumps [actions/checkout](https://github.com/actions/checkout) from 4 to 6.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v4...v6)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.github/workflows/code-linting.yml

@@ -19,7 +19,7 @@ jobs:
         python-version: ["3.10", "3.13", "3.14"]
 
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
     - name: Setup Python ${{ matrix.python-version }}
       uses: actions/setup-python@v5
       with:

.github/workflows/publish.yml

@@ -20,7 +20,7 @@ jobs:
       id-token: write  # Required for Trusted Publisher (OIDC)
 
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
     - name: Setup Python
       uses: actions/setup-python@v5
       with:

.github/workflows/tests.yml

@@ -19,7 +19,7 @@ jobs:
         python-version: ["3.10", "3.12", "3.13"]
 
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
     - name: Setup Python ${{ matrix.python-version }}
       uses: actions/setup-python@v5
       with: