[WIP] Add --pids-limit flag to docker update

[darkowlzz]

- What I did

Added pids-limit flag to docker update command. Also added completion for bash and zsh.

- Description for the changelog

Add --pids-limit flag to docker update

Refer: moby/moby#32519

[codecov-io]

Codecov Report

Merging #181 into master will decrease coverage by 0.01%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##           master     #181      +/-   ##
==========================================
- Coverage   45.67%   45.66%   -0.02%     
==========================================
  Files         171      171              
  Lines       11513    11516       +3     
==========================================
  Hits         5259     5259              
- Misses       5947     5950       +3     
  Partials      307      307

[dnephin]

We should add this to the Compose file as well.

• cli/compose/schema/
• cli/compose/types/
• cli/compose/convert/

[darkowlzz]

Adding PidsLimit to compose file requires swarm Resources to have PidsLimit. Creating another PR in moby/moby for the same.

[dnephin]

Oops, my mistake. I thought this was being added to docker service update. This is fine without the Compose changes. You can remove them from this PR.

[thaJeztah]

@darkowlzz sorry for all the hassle; it looks like you forgot to move the documentation changes to this repository.

We should wait for the changes in moby/moby upstream to be merged first

[darkowlzz]

Removed the commit related to Compose changes and updated commandline/update docs.

[dnephin]

Looks like the moby/moby support hasn't merged yet

[thaJeztah]

carrying in #1765 so that it may still make the cut-off for 19.03 🤗