`package` should support passing docker `--build-arg=[]`

[munkyboy]

[paulcichonski]

I'm guessing we would want ci to support this as well?

[joeygibson]

What's the use-case for this? The v2 docker-compose.yml supports this https://docs.docker.com/compose/compose-file/#/args Does that fill your need, or do you see this really being passed in manually?