Update docs for 0.6.0 (#97)

Author: andrewmchen

README.rst

@@ -17,8 +17,7 @@ In addition, please leave bug reports as issues on our `Github project <https://
 Requirements
 ------------
 
--  Python Version > 2.7.9
--  Python 3 is not supported
+-  Python Version > 2.7.9 or > 3.6
 
 Installation
 ---------------

setup.py

@@ -54,6 +54,7 @@
         'Intended Audience :: Developers',
         'Intended Audience :: System Administrators',
         'Programming Language :: Python :: 2.7',
+        'Programming Language :: Python :: 3.6',
     ],
     keywords='databricks cli',
     url='https://github.com/databricks/databricks-cli'