Configure close-issue-reason of stale bot

[juliapampus]

Feature Request

Set close-issue-reason of stale bot to not_planned.

Which Areas Would Be Affected?

actions

Why Is the Feature Desired?

Some time ago, GitHub introduced the possibility to close issues as "not planned" or "completed". At that time, the bot did not support this distinction. This is why our stale bot currently closes stale issues as "completed". Took a look and the close-issue-reason has been introduced a while ago. We should adapt our bot.

Solution Proposal

Add close-issue-reason: not_planned. An issue for setting this is default was already raised.

Type of Issue

improvement

Checklist

• assigned appropriate label?
• Do NOT select a milestone or an assignee!