also use venv coverage

tox.ini

@@ -36,13 +36,12 @@ commands_pre =
 [testenv:py3]
 deps =
     -r{toxinidir}/test-requirements.txt
-allowlist_externals = coverage3
 setenv = 
     {[testenv]setenv}
     PYTHONPATH=.:plugins/hub/.:plugins/builder/.:plugins/cli/.:cli/.:www/lib
 commands_pre =
     {[testenv]commands_pre}
-    coverage3 erase --rcfile .coveragerc3
+    python -m coverage erase --rcfile .coveragerc3
 commands = 
     python -m pytest -n auto --cov --cov-config .coveragerc3 --cov-report=html