Replace deprecated pkg_resources with packaging module #744
Description
Currently Variety is using pkg_resources to compare versions for upgrading. This module is deprecated and we should switch to the packaging library instead (from packaging.version import parse)
>>> import pkg_resources
<stdin>:1: DeprecationWarning: pkg_resources is deprecated as an API. See https://setuptools.pypa.io/en/latest/pkg_resources.html
Debian bug for reference: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1083982