add pyvista headless display to

Author: MaHaWo

.github/workflows/test.yml

@@ -20,6 +20,7 @@ jobs:
       - uses: actions/setup-python@v4
         with:
           python-version: ${{ matrix.python-version }}
+      - uses: pyvista/setup-headless-display-action@v3
       - run: pip install -e .[tests]
       - run: python -m pytest --cov=sme_contrib --cov-report=xml -v
       - uses: codecov/codecov-action@v3