update grafanabot to use the new close-issue-reason option

[taleena]

What is the chore?:
Github has introduced a new function to closing issues. You can now specify that when issues are closed, they are either complete (default), or not planned.

We should use "closed, not planned" for anything that we've automatically closed as stale - for example, when needing more information and not getting a response. However, we should not use it for things we believe we've fixed and are stale because we're waiting on a response from someone to validate.

Is there anything else we need to know?:
https://github.blog/changelog/2022-05-19-the-new-github-issues-may-19th-update/
actions/stale#764

https://github.com/grafana/grafana/blob/main/.github/bot.md
https://github.com/grafana/grafana/blob/main/.github/commands.json

[github-actions]

This issue has been automatically marked as stale because it has not had activity in the last year. It will be closed in 30 days if no further activity occurs. Please feel free to leave a comment if you believe the issue is still relevant. Thank you for your contributions!

[taleena]

This would still be useful