Add regex support in ServerProtocol(origins=...)

[daH005]

Hello. In my project I tried to pass a regular expression to origins, but it didn't work.
I think this will not be superfluous for the project.
Idea taken from https://github.com/corydolphin/flask-cors/blob/main/flask_cors/core.py

[aaugustin]

Yes, that's a valid improvement.

I don't like the heuristics to tell what's likely a regex. Instead, how about we keep strict backwards-compatibility when the argument is a str and add support for re.Pattern?

[daH005]

I agree with you. I did this and I also added tests.

[aaugustin]

I don't always find time to work on websockets outside of weekends — but I'll get to your MR eventually. Thank you.

[aaugustin]

If you want to run the same checks as CI locally, you can simply run tox (and ignore Python version that aren't installed — this MR won't break on specific Python versions). Or you can use make style (fixes automatically formatting, imports, etc.) +make coverage (runs unittest) + make types (checks types).