When using black & isort, suggest a black-compatible isort config

[amyreese]

https://github.com/jreese/aioitertools/blob/1afcd760ed123b8735735423f032881ab2e8356d/setup.cfg#L12

[thatch]

Any suggestions on how to detect use of black and isort? Them both being in requrements-dev? There being a 'make format' that includes them?

[thatch]

Open questions:

• isort 4?
• how to detect black is in use?