channels_rabbitmq has been humming on production long enough that it
deserves the badge, "1.0".
asgiref has seen a major version bump. channels_rabbitmq doesn't rely
on any of that changed code, but it does need newer dependencies so it can be
installed alongside the latest versions of channels and daphne.
- Bump asgiref to 3.1 and channels to 2.2.
- Bump msgpack from 0.5.2 to 0.6.1