Service `--update-parallelism` defauls to 0
Service `--update-parallelism` defauls to 0

The `--update-parallelism` flaag should default to 0, which is
interpreted by the backend as unlimited. In other words, by default all
services should update simultaneously.

Signed-off-by: Arnaud Porterie (icecrime) <55258e89a8b41a46066b3a9514b15a78c1a88d17@docker.com>
(cherry picked from commit f22d0174f33e084445c5845c95aca346e187fb02)

docker/docker.github.io,shubheksha/docker.github.io,shubheksha/docker.github.io,phiroict/docker,anweiss/docker.github.io,bdwill/docker.github.io,denverdino/docker.github.io,shubheksha/docker.github.io,jzwlqx/denverdino.github.io,JimGalasyn/docker.github.io,troy0820/docker.github.io,troy0820/docker.github.io,docker/docker.github.io,denverdino/denverdino.github.io,Shopify/docker,troy0820/docker.github.io,joaofnfernandes/docker.github.io,shin-/docker.github.io,joeuo/docker.github.io,medallia/docker,gdevillele/docker.github.io,BSWANG/denverdino.github.io,BSWANG/denverdino.github.io,JimGalasyn/docker.github.io,medallia/docker,medallia/docker,anweiss/docker.github.io,bdwill/docker.github.io,gdevillele/docker.github.io,sanscontext/docker.github.io,docker-zh/docker.github.io,jzwlqx/denverdino.github.io,anweiss/docker.github.io,joeuo/docker.github.io,sanscontext/docker.github.io,alexisbellido/docker.github.io,joaofnfernandes/docker.github.io,londoncalling/docker.github.io,sanscontext/docker.github.io,JimGalasyn/docker.github.io,BSWANG/denverdino.github.io,danix800/docker.github.io,Shopify/docker,docker-zh/docker.github.io,thaJeztah/docker.github.io,joeuo/docker.github.io,londoncalling/docker.github.io,shin-/docker.github.io,menglingwei/denverdino.github.io,denverdino/denverdino.github.io,shubheksha/docker.github.io,troy0820/docker.github.io,bdwill/docker.github.io,shin-/docker.github.io,denverdino/denverdino.github.io,joaofnfernandes/docker.github.io,rillig/docker.github.io,sanscontext/docker.github.io,londoncalling/docker.github.io,JimGalasyn/docker.github.io,aduermael/docker.github.io,LuisBosquez/docker.github.io,docker/docker.github.io,danix800/docker.github.io,thaJeztah/docker.github.io,gdevillele/docker.github.io,alexisbellido/docker.github.io,LuisBosquez/docker.github.io,denverdino/docker.github.io,joeuo/docker.github.io,aduermael/docker.github.io,BSWANG/denverdino.github.io,jzwlqx/denverdino.github.io,johnstep/docker.github.io,jzwlqx/denverdino.github.io,BSWANG/denverdino.github.io,Shopify/docker,joaofnfernandes/docker.github.io,jzwlqx/denverdino.github.io,LuisBosquez/docker.github.io,johnstep/docker.github.io,docker-zh/docker.github.io,thaJeztah/docker.github.io,docker/docker.github.io,phiroict/docker,alexisbellido/docker.github.io,menglingwei/denverdino.github.io,denverdino/denverdino.github.io,shubheksha/docker.github.io,menglingwei/denverdino.github.io,gdevillele/docker.github.io,stainboy/docker,bdwill/docker.github.io,aduermael/docker.github.io,sanscontext/docker.github.io,LuisBosquez/docker.github.io,stainboy/docker,gdevillele/docker.github.io,danix800/docker.github.io,shin-/docker.github.io,joaofnfernandes/docker.github.io,londoncalling/docker.github.io,anweiss/docker.github.io,rillig/docker.github.io,phiroict/docker,rillig/docker.github.io,johnstep/docker.github.io,londoncalling/docker.github.io,stainboy/docker,docker-zh/docker.github.io,denverdino/docker.github.io,LuisBosquez/docker.github.io,menglingwei/denverdino.github.io,rillig/docker.github.io,JimGalasyn/docker.github.io,thaJeztah/docker.github.io,johnstep/docker.github.io,phiroict/docker,shin-/docker.github.io,denverdino/denverdino.github.io,docker-zh/docker.github.io,johnstep/docker.github.io,medallia/docker,docker/docker.github.io,phiroict/docker,joeuo/docker.github.io,menglingwei/denverdino.github.io,denverdino/docker.github.io,aduermael/docker.github.io,bdwill/docker.github.io,alexisbellido/docker.github.io,anweiss/docker.github.io,denverdino/docker.github.io,thaJeztah/docker.github.io,alexisbellido/docker.github.io,danix800/docker.github.io