Merge pull request #2044 from hodgestar/feature/v5-simplify-version-p…

…arsing

Simplify version parsing (v5).

setup.py

@@ -141,12 +141,7 @@ def _determine_version(options):
     version_filename = os.path.join(options['rootdir'], 'VERSION')
     with open(version_filename, "r") as version_file:
         version_string = version_file.read().strip()
-    version = packaging.version.parse(version_string)
-    # LegacyVersion was removed in packaging 22, but is still returned by
-    # packing <= 21
-    LegacyVersion = getattr(packaging.version, "LegacyVersion", type(None))
-    if isinstance(version, LegacyVersion):
-        raise ValueError("invalid version: " + version_string)    
+    version = packaging.version.Version(version_string)
     options['short_version'] = str(version.public)
     options['release'] = not version.is_devrelease
     if not options['release']: