remove strict_map_key requirement for deserialize

[envirocoder]

Trying to send a dict with integer keys,
e.g.

async_to_sync(channel_layer.group_send)(
        "name",
        {"type":"test",
        "data": {1:10, 2:20},
        }

I got

  File "msgpack/_unpacker.pyx", line 195, in msgpack._cmsgpack.unpackb
ValueError: int is not allowed for map key

not familiar with the channels or redis code to know if there will be implementations else where; is it safe to relax the checking in msgpack unpacking with strict_map_key=False ?

[envirocoder]

just noticed, duplicate of #233