Allow proxy authentification

[corentingosselin]

Hello,
Great addon for asyncio !
I would like to allow authentification like:
proxies=[ "user:password@xx.xx.xx.xx:80", "user:password@xx.xx.xx.xx:80" # ... ],
Could you add this feature ?

[jgontrum]

Hi!

Do you know what format proxies usually use when setting them directly in aiohttp? I've came across this package here: https://pypi.org/project/aiohttp-proxy/ - Do you think this would be a better solution for this issue?