Document Python 2 deprecation (#6910)

Author: crwilcox

README.rst

@@ -47,6 +47,15 @@ dependencies.
 .. _`virtualenv`: https://virtualenv.pypa.io/en/latest/
 
 
+Supported Python Versions
+^^^^^^^^^^^^^^^^^^^^^^^^^
+Python >= 3.4
+
+Deprecated Python Versions
+^^^^^^^^^^^^^^^^^^^^^^^^^^
+Python == 2.7. Python 2.7 support will be removed on January 1, 2020.
+
+
 Mac/Linux
 ^^^^^^^^^
 

setup.py

@@ -75,6 +75,7 @@
         'Programming Language :: Python :: 3.4',
         'Programming Language :: Python :: 3.5',
         'Programming Language :: Python :: 3.6',
+        'Programming Language :: Python :: 3.7',
         'Operating System :: OS Independent',
         'Topic :: Internet',
     ],
@@ -83,6 +84,7 @@
     namespace_packages=namespaces,
     install_requires=dependencies,
     extras_require=extras,
+    python_requires='>=2.7,!=3.0.*,!=3.1.*,!=3.2.*,!=3.3.*',
     include_package_data=True,
     zip_safe=False,
 )