This commit cleanup below:
- Remove python 2.7 stanza from setup.py
- Add requires on python >= 3.6 to setup.cfg so that pypi and pip
know about the requirement
- Add "ignore_basepython_conflict=True" to tox.ini
Change-Id: Ic4fcc1fb15f214ca4204f56ee1ea15dc6a782fc2
zhangbailin