Add Python 3.6 classifier to setup.cfg
Add Python 3.6 classifier to setup.cfg

Change-Id: I6d5ca5847d28c37e6415e400731f135274c72229
Story: 2004148
Task: 28173

openstack/python-monascaclient,stackforge/python-monascaclient,openstack/python-monascaclient,stackforge/python-monascaclient