The problem

Currently, everyone who uses actions/stale will need to know to configure the close-issue-reason setting to not_planned to get the new close type - https://github.blog/changelog/2022-05-19-the-new-github-issues-may-19th-update/

The solution

Make the default value 'not_planned' instead of ''. The reason matches the use in stale - "Won't fix, canceled, duplicate, stale"