Missing documentation on how to set `connection_kwargs` params.

[Sergey Lyapustin]

What is the right way to specify connection_kwargs?

Based on the changelog - it was implemented a while ago, but there are no examples on how to set that and no mentions in the docs.

I'm happy to submit PR, but I can't figure out how to set them on my own 🤔

1.3.0 (2017-04-07)

• Change the format of connection arguments to be a single dict called
  connection_kwargs rather than individual options, as they change by
  connection type. You will need to change your settings if you have any of
  socket_connect_timeout, socket_timeout, socket_keepalive or
  socket_keepalive_options set to move them into a connection_kwargs dict.

[Carlton Gibson]

connection_kwargs will just be passed to the underlying library no?

[Sergey Lyapustin]

@carltongibson How it should look in the CHANNEL_LAYERS configuration?

CHANNEL_LAYERS = {
    "default": {
        "BACKEND": "channels_redis.core.RedisChannelLayer",
        # how to pass `socket_connect_timeout`, `socket_timeout` and etc?
    }
}

[Sergey Lyapustin]

This might be relevant to #331

[Carlton Gibson]

This should be resolved by #370.