[Copilot]

test-coverage was failing before tests executed because the workflow adds ppa:cran/librdf, which has no noble release on ubuntu-latest and causes apt update to exit with code 100.
This PR removes that brittle repo setup so coverage runs proceed with standard dependency resolution.

• Root-cause fix

  • Deleted the Linux-only step in .github/workflows/test-coverage.yaml that ran:
    • sudo add-apt-repository ppa:cran/librdf
    • sudo apt update

• Workflow behavior after change

  • test-coverage now relies on r-lib/actions/setup-r-dependencies@v2 (needs: coverage, any::XML, any::covr) without custom apt PPAs.

• Relevant diff

  -      - name: Install libraptor on Linux
  -        if: runner.os == 'Linux'
  -        run: |
  -          sudo add-apt-repository ppa:cran/librdf
  -          sudo apt update