- run lint using latest Python 3.7
- updated env list in tox.ini
- added py38-dev
- removed py36-dev
- moved aiohttp to requirements_test.txt
Signed-off-by: Brett Randall <javabrett@gmail.com>
This way we can avoid code duplication.
Also, this change makes tests faster due to ignoring the sdist step
and adds Python 3.2, 3.4 and PyPy 3 to build matrix.