[tox]
envlist=py{27,35,36}
[testenv]
extras=
    dev
commands=pytest
[pytest]
addopts=-n 2

[tox]
envlist=py{36,37,38}
[testenv]
extras=
    dev
commands=pytest
[pytest]
addopts=-n 2

Update supported Python versions in Tox configuration
Update supported Python versions in Tox configuration
