Add example command to go-server playbook

playbooks/go-server.yml

 # This playbook installs go-server
 # https://www.go.cd/
 #
+# https://openedx.atlassian.net/wiki/spaces/EdxOps/pages/157526357/How+to+Upgrade+GoCD
+# Example command: ansible-playbook -i <ip_here>, -c ssh go-server.yml -e@/path/to/secure/ansible/vars/admin/admin.yml -e@/path/to/secure/ansible/vars/admin/edx_admin.yml -e@/path/to/secure/ansible/vars/admin/pipeline/gocd.yml -D
 
 - name: Install go-server
   hosts: all