Support paho.mqtt > 2.1.x

[espenairmine]

Is your feature request related to a problem? Please describe.
We are currently developing a solution were we need to bridge from IoThub to a local mqtt broker, and would like to use aiomqtt to connect to the local mqtth broker (https://pypi.org/project/aiomqtt/)

Describe the solution you'd like
Support for paho.mqtt >2.1.x in azure-iot-device:
azure-iot-device 2.14.0 requires paho-mqtt<2.0.0,>=1.6.1, but you have paho-mqtt 2.1.0 which is incompatible.

Describe alternatives you've considered
We can port the other code we have to paho 1.6.x, but aiomqtt provide a nice and clean (and simpler) approach