Parameterize PullReq status support

[cloverrose]

Hi, thank you for this nice github action.
I want to run this action in PullReq commit to check generated sync PullReqs are ok or not before merging the PullReq.
I can do it even current implementation.
However, I want to open these sync PullReqs as drafts. Because I don't want to notify our team members by these PullReqs.

Could you please support PullReq status (ready for review/draft) as action input parameter?