Remove pipe from XVFB action.

This isn't a normal run argument so the pipe might have been messing
up the action.

Author: HexDecimal

.github/workflows/python-package.yml

@@ -54,6 +54,5 @@ jobs:
     - name: Test with pytest
       uses: GabrielBB/xvfb-action@v1
       with:
-        run: |
-          pytest --cov-report=xml
+        run: pytest --cov-report=xml
     - uses: codecov/codecov-action@v1