Is your feature request related to a problem? Please describe.

I would like to cut a pre-release

Describe the solution you'd like

Have a (documented) way to configure release-please so that it knows that I am publishing a pre-release.

It could be as simple as an argument of the CLI (example: --prerelease=alpha) and/or it could be via configuration file to map branch name with release type.

Describe alternatives you've considered

Well, except using another tool than release-please, I don't see how to achieve that.

Additional context

I'm not sure what to add here. The context is releasing a software early as a pre-release...