ci: bump codecov/codecov-action from 5 to 6

Bumps [codecov/codecov-action](https://github.com/codecov/codecov-action) from 5 to 6.
- [Release notes](https://github.com/codecov/codecov-action/releases)
- [Changelog](https://github.com/codecov/codecov-action/blob/main/CHANGELOG.md)
- [Commits](https://github.com/codecov/codecov-action/compare/v5...v6)

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

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

.github/workflows/python-unit-test.yml

@@ -92,7 +92,7 @@ jobs:
           TOXENV="$toxenvs" lsr_ci_runtox
 
       - name: Upload coverage reports to Codecov
-        uses: codecov/codecov-action@v5
+        uses: codecov/codecov-action@v6
 
   python-26:
     runs-on: ubuntu-latest