Add Python 3.14 classifier in setup.py

Author: EwoutH

setup.py

@@ -55,6 +55,7 @@
         "Programming Language :: Python :: 3.11",
         "Programming Language :: Python :: 3.12",
         "Programming Language :: Python :: 3.13",
+        "Programming Language :: Python :: 3.14",
     ],
     project_urls={
         "Source": "https://github.com/certifi/python-certifi",