Breaking change with paho-mqtt release 2.0

[isolationism]

Thank you for your work on this project. 🙇

Discovered this afternoon after paho-mqtt 2 was installed in a new container build.

The docs cite a new CallbackAPIVersion parameter, which corresponds with what I'm seeing in a stack trace:

   File "/usr/local/lib/python3.11/site-packages/mqttasgi/server.py", line 37, in __init__
    self.client = mqtt.Client(client_id=self.client_id, transport=self.transport, userdata={
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 TypeError: Client.__init__() missing 1 required positional argument: 'callback_api_version'

[sivulich]

Hi @isolationism, thanks for flagging this.
I see two options here. We can consider fixing the paho version or supporting both.
I'll let you know what we decide.