Bump actions/checkout from 5 to 6

Bumps [actions/checkout](https://github.com/actions/checkout) from 5 to 6.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v5...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] <[email protected]>

Author: dependabot[bot]

.github/workflows/github-ci.yml

@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-24.04
     steps:
 
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
 
     - name: Use Node.js LTS 20.11.0
       uses: actions/[email protected]

.github/workflows/reuse-compliance.yml

@@ -16,6 +16,6 @@ jobs:
     name: Compliance Check
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
     - name: Execute REUSE Compliance Check
       uses: fsfe/reuse-action@v6