setup.py: adding python 3.13

Author: mrjbq7

setup.py

@@ -173,6 +173,7 @@ def build_extensions(self):
         "Programming Language :: Python :: 3.10",
         "Programming Language :: Python :: 3.11",
         "Programming Language :: Python :: 3.12",
+        "Programming Language :: Python :: 3.13",
         "Programming Language :: Cython",
         "Topic :: Office/Business :: Financial",
         "Topic :: Scientific/Engineering :: Mathematics",