Added label search example for update_topology in README
Added label search example for update_topology in README

interop-dev/django-netjsongraph,netjson/django-netjsongraph,netjson/django-netjsongraph,netjson/django-netjsongraph,interop-dev/django-netjsongraph,netjson/django-netjsongraph,interop-dev/django-netjsongraph