Is your feature request related to a problem? Please describe.
Some packagers such as docker publish their files to a given remote service (in the case of docker it's a docker registry) besides publishing them to a git repo. Sometimes you'd like to skip publishing to that remote service.

Describe the solution you'd like
Add a flag to skip the publishing step.

Describe alternatives you've considered
Manually invoke prepare and package while skipping publish steps.

cc: @maxandersen