Standardize setup.cfg (#212)

setup.cfg

@@ -10,13 +10,20 @@ author_email = asottile@umich.edu
 maintainer = Adam Johnson
 maintainer_email = me@adamj.eu
 license = MIT
-license_file = LICENSE
 classifiers =
+    Development Status :: 5 - Production/Stable
+    Intended Audience :: Developers
     License :: OSI Approved :: MIT License
-    Programming Language :: Python :: 3
+    Natural Language :: English
+    Operating System :: OS Independent
     Programming Language :: Python :: 3 :: Only
-    Programming Language :: Python :: Implementation :: CPython
-    Programming Language :: Python :: Implementation :: PyPy
+    Programming Language :: Python :: 3
+    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
+    Typing :: Typed
 project_urls =
     Changelog = https://github.com/adamchainz/blacken-docs/blob/main/HISTORY.rst