Fix license-file metadata: suppress setuptools auto-discovery

setuptools auto-adds license-file to wheel metadata when it finds
a LICENSE file, which twine >=6 rejects. Setting license_files=[]
prevents the auto-discovery while keeping the explicit license field.

Author: GeiserX

setup.py

@@ -15,6 +15,7 @@
     long_description_content_type="text/markdown",
     url="https://github.com/GeiserX/Wayback-Diff",
     license="GPL-3.0-only",
+    license_files=[],
     packages=find_packages(),
     classifiers=[
         "Development Status :: 3 - Alpha",