support custom descriptions for custom types

[gofford]

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

I am combining this action with https://github.com/google-github-actions/release-please-action to handle version increments. I would like to filter the possible types to a subset of the full conventional commit spec; specifically, I'd like to support only feat, fix, perf, docs and chore.

It is currently possible to define these as custom types, however doing so removes the useful description of each type in the outputs.error_message.

Describe the solution you'd like

I would like to either be able to subset the supported types (and retain the description). Or provide custom descriptions to my custom types.

Describe alternatives you've considered

None - this isn't currently possible.