Remove deprecated license classifier.

Author: ionelmc

setup.py

@@ -94,7 +94,6 @@ def run(self):
         'Development Status :: 5 - Production/Stable',
         'Framework :: Pytest',
         'Intended Audience :: Developers',
-        'License :: OSI Approved :: MIT License',
         'Operating System :: Microsoft :: Windows',
         'Operating System :: POSIX',
         'Operating System :: Unix',