Drop use of async_generator?

[jas4711]

Hi! There was a bug report about async_generator not being maintained any more:

https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1130738

In Debian we now use the following patch to disable use of async_generator in netfilerquere, what do you think?

https://sources.debian.org/src/python-netfilterqueue/1.1.0-5/debian/patches/drop_async_generator.patch

/Simon