Fix Python3.7 compatibility issue

[daun-io]

passing "async" argument can make invalid argument error on python 3.7
#1017 async invalid syntax #1017

[joshthecoder]

Looks good thanks :)

[alexott]

Can we get a release with this bug fix?

[shuuji3]

For those who need to use Tweepy in Python3.7 immediately, here is a workaround:

$ pip install git+https://github.com/tweepy/tweepy

This command will install the GitHub's latest version (as v3.6.0) instead of PyPI's v3.6.0.

ref. VCS Support ― pip install — pip 18.0 documentation

[ilf]

Python 3.7 has been out for more than three months now, so have the initial patches here. Is there anything we can do to help get out a tweepy release that works with current Python? Thanks!

[denyramandaa]

Thank you! it's helped me!

[hugovk]

There is now a Tweepy release supporting Python 3.7.

Thank you, @joshthecoder!