Support 3.12 (#592)

setup.py

@@ -80,9 +80,10 @@ setup(
         "Programming Language :: Python :: 3.9",
         "Programming Language :: Python :: 3.10",
         "Programming Language :: Python :: 3.11",
+        "Programming Language :: Python :: 3.12",
     ],
     keywords="remove, background, u2net",
-    python_requires=">=3.8, <3.12",
+    python_requires=">=3.8, <3.13",
     packages=find_packages(),
     install_requires=install_requires,
     entry_points=entry_points,