Compatibility of python3 on mininet

[Yummy-h]

Expected/Desired Behavior: mininet support python3

Actual Behavior: mininet support python2

Detailed Steps to Reproduce the Behavior: The mininet is used to simulate the network topology. It is not necessary to use the graphical tool miniedit, but only use the command line to implement the network topology, so that each host can communicate with each other.

Additional Information: Compatibility of python3 on mininet

[teto]

master version supports python3

[teto]

but it would be great if mininet could start using more advanced features of python3:
https://pythonclock.org/ . For instance python3 introduced the IPv4address module to generate network iPs (would be nice for node.setIP to accept it) etc, type hinting, f-strings. Would be nice to bump the minimal version to python3.