Updating readme to reflect support for Python 3.9 (#545)
Updating readme to reflect support for Python 3.9 (#545)

According to the badge on the README Python 3.9 is supported and 3.9 is tested in CI, but it is not listed as being supported in the text of the README so I added it there.

Co-authored-by: Sambhav Kothari <236bbd84da06bef9cd30db11e0ca5e3b235d8199@gmail.com>
PyCQA/pydocstyle