Fix example of relative WORKDIR
Fix example of relative WORKDIR

Docker-DCO-1.1-Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com> (github: LK4D4)

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