disable tox configuration for pypy3
tox can not invoke test suite for pypy3 on Windows 10 - again.
# and then run "tox" from this directory.
[tox]
-envlist = py36, py37, py38, pypy3
+# pypy3: environment error on Windows 10 - again
+envlist = py36, py37, py38
[testenv]
commands = pytest tests integration_tests
