Add Winloop To the list of loop setups and optional-dependencies

[Vizonex]

Summary

I added winloop as another option for loop setups since winloop is a fork of uvloop that I made almost 2 years ago for using
uvloop with windows. Even though I've made a tutorial in my own readme on how to use winloop with uvicorn and fastapi, I thought it would be time to actually integrate my library to this one. However I am questioned about how we go about making a test and also how I should go about updating the documentation for this new addition that I have added to this library so I have those two things on the checklist unchecked, other than that I am excited to see where this will go in the future as well as seeing how people will go about using this in the future.

Checklist

• I understand that this PR may be closed in case there was no previous discussion. (This doesn't apply to typos!)
• I've added a test for each change that was introduced, and I tried as much as possible to make a single atomic change.
• I've updated the documentation accordingly.

[graingert]

I think it's best to wait for this PR: #2435 which will then work with --loop=winloop:new_event_loop