Avoid use of deprecated setup file keyword.

GrahamDumpleton · GrahamDumpleton · commit f7e9caba4ae2 · 2023-11-05T09:07:25.000+11:00
diff --git a/setup.cfg b/setup.cfg
@@ -10,7 +10,7 @@ description = Module for decorators, wrappers and monkey patching.
 long_description = file: README.rst
 long_description_content_type = text/x-rst
 license = BSD
-license_file = LICENSE
+license_files = LICENSE
 platform = any
 keywords = wrapper, proxy, decorator
 classifiers =
