Added the 'Framework :: Pytest' classifier

Author: smarie

setup.py

@@ -100,6 +100,8 @@
         'Programming Language :: Python :: 3.5',
         'Programming Language :: Python :: 3.6',
         'Programming Language :: Python :: 3.7',
+
+        'Framework :: Pytest'
     ],
 
     # What does your project relate to?