Update setup.py

Author: ChrisRackauckas

setup.py

@@ -12,7 +12,6 @@ def readme():
       classifiers=[
         'Development Status :: 4 - Beta',
         'License :: OSI Approved :: MIT License',
-        'Programming Language :: Python :: 3.9',
         'Programming Language :: Python :: 3.10',
         'Programming Language :: Python :: 3.11',
         'Programming Language :: Python :: 3.12',