chore(build): update tox

Author: accraze

tox.ini

@@ -71,7 +71,6 @@ commands =
     python setup.py check --strict --metadata --restructuredtext
     check-manifest {toxinidir}
     flake8 src tests setup.py
-    isort --verbose --check-only --diff --recursive src tests setup.py
 
 [testenv:coveralls]
 deps =