Replace pkg_resources with packaging

Closes varietywalls#744

Author: jlu5

README.md

@@ -63,7 +63,7 @@ To install Variety from source, you will need Git, Python 3.8+ and [distutils-ex
     - PyGObject, built with Cairo integration
     - ConfigObj
     - Pillow
-    - pkg_resources (from setuptools)
+    - packaging
     - Requests
     - *Optional*: httplib2 (for more quotes sources)
 - *Optional*: imagemagick (for wallpaper filters)

requirements.txt

@@ -6,3 +6,4 @@ requests
 pygobject
 pillow
 httplib2
+packaging

variety/Util.py

@@ -765,7 +765,10 @@ def collapseuser(path):
 
     @staticmethod
     def compare_versions(v1, v2):
-        from pkg_resources import parse_version
+        try:
+            from packaging.version import parse as parse_version
+        except ImportError:
+            from pkg_resources import parse_version
 
         pv1 = parse_version(v1)
         pv2 = parse_version(v2)