chore: bump actions/upload-artifact in the github-actions group

Bumps the github-actions group with 1 update: [actions/upload-artifact](https://github.com/actions/upload-artifact).


Updates `actions/upload-artifact` from 5 to 6
- [Release notes](https://github.com/actions/upload-artifact/releases)
- [Commits](actions/upload-artifact@v5...v6)

---
updated-dependencies:
- dependency-name: actions/upload-artifact
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: github-actions
...

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

Author: dependabot[bot]

.github/workflows/ci_fuzz_linux.yml

@@ -64,7 +64,7 @@ jobs:
     - name: Upload broken PDFs as artifact
       # Always upload, even if job fails.
       if: failure() || always()
-      uses: actions/upload-artifact@v5
+      uses: actions/upload-artifact@v6
       with:
         name: tests_fuzz_broken_pdfs
         path: build/tests_fuzz