-r requirements.txt
pytest-cov==2.7.1
tox==3.11.1
tox-travis==0.12
codecov==2.0.15
coverage==4.5.3

-r requirements.txt
pytest-cov==2.7.1
tox==3.12.1
tox-travis==0.12
codecov==2.0.15
coverage==4.5.3

Update tox from 3.11.1 to 3.12.1
Update tox from 3.11.1 to 3.12.1