Build(deps): Bump codecov/codecov-action in the github-actions group

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


Updates `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](codecov/codecov-action@v5...v6)

---
updated-dependencies:
- dependency-name: codecov/codecov-action
  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-c.yml

@@ -79,7 +79,7 @@ jobs:
           CTEST_OUTPUT_ON_FAILURE=1 cmake --build build -- tests test coverage-xml
       - name: Upload test coverage to Codecov
         if: github.repository == 'greenbone/gvm-libs'
-        uses: codecov/codecov-action@v5
+        uses: codecov/codecov-action@v6
         with:
           files: build/coverage/coverage.xml
           token: ${{ secrets.CODECOV_TOKEN }}