Allow scope in selectors

[dannysauer]

I'd like to be able to separate commit types by scope. For example, I'd like to be able to include chore(deps) updates in a release, but ignore chore(build-deps). Without support for the scope filter, I have to either use a non-standard commit type or mix types for differnt-kinds of dependency updates.

Correct me if I'm wrong, but it seems like this might magically just start to work if #2544 is merged? Or at least it'll be easier to implement after that. 🤷

[dannysauer]

This is peripherally related to #1989, and I think implementing and documenting this would also technically fix #1735. But I'm pretty sure my use case is still mostly separate enough to warrant the new ticket. :)

[dannysauer]

Maybe #1186, too.