Clean tox file

Author: dstansby

tox.ini

@@ -10,10 +10,5 @@ python =
 
 [testenv]
 extras = testing
-allowlist_externals =
-    cp
-    ls
 commands =
-    cp -R {toxinidir}/src/napari_matplotlib/tests/baseline {envdir}/baseline
-    ls {toxinidir}/src/napari_matplotlib/tests/baseline
     python -m pytest --mpl --mpl-generate-summary=html --mpl-results-path={toxinidir}/reports -v --color=yes --cov=napari_matplotlib --cov-report=xml