Remove SOCK_NONBLOCK from socket creation on tests

[ereslibre]

This fixes running tests on Mac OS X, which lacks the SOCK_NONBLOCK
socket flag creation.

[andrewgodwin]

I wish I could remember why it was there in the first place, but I can't think of a good reason and the tests seem to pass, so... sure?

You'll need to pin the version of Click to fix that linting error for now though - see psf/black#2964

[ereslibre]

@andrewgodwin I'm sorry I don't know what's the most appropriate way to pin click, not familiar with python/django development, and I don't see a conclusive way to do so out of the box. A pointer will do, thanks!

[Kludex]

Here:

asgiref/setup.cfg

Lines 37 to 41 in cde961b

	[options.extras_require]
	tests =
	pytest
	pytest-asyncio
	mypy>=0.800

Add click==<version_that_works>

[ereslibre]

Thank you @Kludex. Done.

[andrewgodwin]

Looks like I got it wrong there - it was the pre-commit hook that needed fixing! I've made the changes for you - thanks for the PR!

[ereslibre]

That was my first try, but I did undo it just because I didn't know if it was what you wanted :)

Thanks for the reviews!