Update minimum python. Update classifiers.

Author: adiroiban

setup.cfg

@@ -10,15 +10,17 @@ maintainer = Thomas Grainger
 maintainer_email = cython-test-exception-raiser@graingert.co.uk
 url = https://github.com/twisted/cython-test-exception-raiser
 license = MIT
-python_requires = >=3.6
+python_requires = >=3.8
 classifiers =
     Programming Language :: Python :: 3
     Programming Language :: Python :: 3 :: Only
-    Programming Language :: Python :: 3.6
-    Programming Language :: Python :: 3.7
     Programming Language :: Python :: 3.8
     Programming Language :: Python :: 3.9
     Programming Language :: Python :: 3.10
+    Programming Language :: Python :: 3.11
+    Programming Language :: Python :: 3.12
+    Programming Language :: Python :: 3.13
+    Programming Language :: Python :: 3.14
 
 [options]
 packages = find: