Remove usage of deprecated pkg_resource in setup.py (#2349)

* Remove usage of deprecated pkg_resource

In setup.py just remove a check for a 2018+ release of setuptools.

Author: xrmx

setup.py

@@ -44,11 +44,8 @@
 import codecs
 import os
 
-import pkg_resources
 from setuptools import setup
 
-pkg_resources.require("setuptools>=39.2")
-
 
 def get_version():
     """