Bump actions/checkout from 3 to 6 (#45)

Bumps [actions/checkout](https://github.com/actions/checkout) from 3 to 6.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v3...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>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/publish.yml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
     environment: release
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
     - name: Set up Python
       uses: actions/setup-python@v5
       with:

.github/workflows/test.yml

@@ -24,7 +24,7 @@ jobs:
 
     steps:
     - name: Checkout
-      uses: actions/checkout@v3
+      uses: actions/checkout@v6
 
     - uses: actions/setup-python@v4
       with: