This is deprecated since aiohttp 4.0. If it doesn't exist just define a
no-op decorator that does nothing (after the other aiohttp imports
though!). By doing this, it's safe to ignore the DeprecationWarning
without needing to require the latest aiohttp once they remove
`@middleware`.
* re-implement simple CORS middleware for blackd
* remove aiohttp-cors from setup.py
* Remove aiohttp-cors from Pipfile.lock
Co-authored-by: Richard Si <63936253+ichard26@users.noreply.github.com>
