3J - Fix invalid licence format thing

Author: Omena0

setup.cfg

@@ -4,12 +4,14 @@ description = Split a single tcp/ip connection between multiple servers.
 long_description = file: README.md
 long_description_content_type = text/markdown
 author = Omena0
-license = PolyForm Noncommercial License 1.0.0
+license = PolyForm Noncommercial 1.0.0
+license_files = COPYING.md
 url = https://github.com/Omena0/NetSplit
 classifiers =
     Programming Language :: Python :: 3
+    Programming Language :: Python :: 3.13
     Programming Language :: Python :: 3.13.5
-    License :: PolyForm Noncommercial License 1.0.0
+    License :: Other/Proprietary License
     Operating System :: OS Independent
 
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