Update service_create.md
Update service_create.md

More info on endpoint setting, and service discovery on swarm mode overlay network.

Signed-off-by: Richard Mathie <4bb975c8b2abba1260b65d258b1a0fadc1a84dc6@amey.co.uk>

docker/cli,cpuguy83/cli,Zebrilee/cli,allencloud/cli,docker/cli,dnephin/cli,redpanda/cli,redpanda/cli,Zebrilee/cli,e11137/cli,ashfall/cli,cpuguy83/cli,allencloud/cli,thaJeztah/cli,riyazdf/cli,e11137/cli,dnephin/cli,riyazdf/cli,thaJeztah/cli,ashfall/cli