Add fish shell completions from https://github.com/barnybug/docker-fish-completion.
Add fish shell completions from https://github.com/barnybug/docker-fish-completion.

Docker-DCO-1.1-Signed-off-by: Barnaby Gray <barnaby@pickle.me.uk> (github: barnybug)

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