Remove dependencies on py23_compat, so it works with Python 3.6

[miguelhernandez-work]

Hi,
I attempted to use this library with Python 3.6.8 and its breaking on

ImportError: cannot import name py23_compat

My use-case is to use this with netbox.
Can we please have a version that doesn't require py23_compat?
Thanks in advance.

[skoef]

Has napalm dropped python 2 support itself? If so, the easiest fix would be to comply and drop python 2(.3) support.

I'm no python dependency expert, but perhaps if py23_compat was part of the requirements.txt file, it would automatically be installed alongside this plugin?

[miguelhernandez-work]

I was testing with this with my Dell S4048-ON switches (FTOS / Dell OS v9.x) and had to specify napalam==2.5 in my local_requirements.txt to get it to work with the raw API command, however that then possibly caused issues with netbox not rendering the lldp results within the GUI.

I tested adding py23_compat to the requirements file and it spit out error msg:
Could not find a version that satisfies the requirement py23_compat
I guess this is because napalm, as of version 3.0 (as of May this year), supports Python 3.6+ only.

[baccenfutter]

@skoef is a fix in the pipeline?