Stale issue/pr action

[snide]

Summary

Adds a Github action that checks for stale issues and PRs using https://github.com/actions/stale, which is Github's officially supported action for stale checks. To run this in a dry run mode, I've turned on Github logging for the repo, and set debug-only: true for the action. The docs on https://github.com/actions/stale#debugging suggest this means the action will not be run, and only be logged. This should allow us to watch how this would effect our repo.

Checklist

[cchaos]

Where do they put the logs?

[snide]

They live in the actions interface. You need to add a key to the repo to turn them on. I'd like to configure the messages first, then we should be safe to merge this, watch the log output as it runs (once every 8 hours) and then make some tweaks.

[kibanamachine]

Preview documentation changes for this PR: https://eui.elastic.co/pr_4625/

[cchaos]

LGTM. Interested in seeing the statistics in the end.

[snide]

I have added a duplicate of this action on a shorter timer over in our gatsby-starter https://github.com/elastic/gatsby-eui-starter/actions/workflows/stale.yml

Once I see it successfully run and generating logs I'll merge this PR so we can see some dry-run stats for our meeting.

[thompsongl]

Cool, let's try it out

[kibanamachine]

Preview documentation changes for this PR: https://eui.elastic.co/pr_4625/

[snide]

Here's an example of the logs generated for elastic/gatsby-eui-starter

https://github.com/elastic/gatsby-eui-starter/runs/2061211848?check_suite_focus=true

I can see that it successfully ran in debug mode and took no action on the issues/prs. I'm gonna take that as reason this is safe to merge.

[kibanamachine]

Preview documentation changes for this PR: https://eui.elastic.co/pr_4625/