html_url & number not set when PR already exists

[scmorse]

IMO users of this action should be able to rely on these outputs, whether or not the created output is true/false.

[thomaseizinger]

So if I understand correctly, you want the action to fetch the number and url of the existing PR, even if it was not created?

I think that makes sense. Personally I don't have a usecase for this but I'd accept a PR for it.