Add some more attributes to setup

Author: Cito

setup.py

@@ -14,7 +14,11 @@
     url='https://github.com/pytest-dev/pytest-describe',
     author='Robin Pedersen',
     author_email='[email protected]',
-    license='MIT license',
+    maintainer='Christoph Zwerschke',
+    maintainer_email='[email protected]',
+    license='MIT',
+    license_file='LICENSE',
+    platforms=['unix', 'linux', 'osx', 'cygwin', 'win32'],
     install_requires=[
         'pytest>=4.0.0',
     ],
@@ -35,6 +39,7 @@
         'Topic :: Software Development :: Libraries',
         'Topic :: Utilities',
         'Programming Language :: Python :: 3',
+        'Programming Language :: Python :: 3 :: Only',
         'Programming Language :: Python :: 3.6',
         'Programming Language :: Python :: 3.7',
         'Programming Language :: Python :: 3.8',