README: Fixed OpsWorks code example
README: Fixed OpsWorks code example

mixpanel-platform/chef-handler-sns,zuazo/chef-handler-sns,mevic/chef-handler-sns,mixpanel-platform/chef-handler-sns,mevic/chef-handler-sns,zuazo/chef-handler-sns,onddo/chef-handler-sns,onddo/chef-handler-sns