Update classifiers.

Author: Rémy HUBSCHER

setup.py

@@ -28,8 +28,8 @@
     classifiers=[
         "Programming Language :: Python",
         "Programming Language :: Python :: 3",
-        "Programming Language :: Python :: 3.5",
         "Programming Language :: Python :: 3.6",
+        "Programming Language :: Python :: 3.7",
         "Programming Language :: Python :: Implementation :: CPython",
         "Topic :: Internet :: WWW/HTTP",
         "License :: OSI Approved :: Apache Software License",