Bump fsfe/reuse-action from 5 to 6

Bumps [fsfe/reuse-action](https://github.com/fsfe/reuse-action) from 5 to 6.
- [Release notes](https://github.com/fsfe/reuse-action/releases)
- [Commits](fsfe/reuse-action@v5...v6)

---
updated-dependencies:
- dependency-name: fsfe/reuse-action
  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/ci_license.yml

@@ -35,7 +35,7 @@ jobs:
         uses: actions/checkout@v5
 
       - name: REUSE Compliance Check
-        uses: fsfe/reuse-action@v5
+        uses: fsfe/reuse-action@v6
 
       - name: Check Markdown files for doxygen
         run: ${{ github.workspace }}/test/scripts/check_markdown_doxygen.sh ${{ github.workspace }}