Create a bot to handle stalled issues and pull requests

[GuySartorelli]

In #75 we looked at how we can deal with stalled issues and pull requests. We concluded that we want a bot to handle a lot of this for us. Now we need to build it.

Overall document outlining how the bot should work

Currently only the CMS Squad have access to this - but @silverstripe/core-team please let me know if you want access to it.
https://docs.google.com/document/d/1Ktv1SkQNMZRuG6svhIJJCc7N4sUkuKu36lNgOIoRy-0/edit

There's also some additional notes in https://silverstripe.atlassian.net/wiki/spaces/CMS/pages/3347742776/2024-06-20+-+Stalled+contributions+Retro - though most of these notes resulted in changes in the document itself.

Note

• There's a lot this bot could do in the future - but for now we're exclusively focusing on stalled issues and pull requests
• If there's an existing bot that can be adapted to our specific needs, we should consider using that.

Some examples of similar things

• probot
• actions/stale
• carsonbot

Examples of comms when tools like this are introduced

• from spatie
• from Symfony

Acceptance criteria

• A bot exists which has the functionality outlined in the document above
• The bot handles issues and pull requests
• The bot correctly identifies when a pull request is meant to be associated with an issue - within reason (see list below)
• Appropriate documentation is created or updated, e.g. in the contributing section
• Comms minimally in the form of a blog post, a forum post, and links in the public slack are published which outline:
  • what the bot does
  • how we intend to use it
  • when it will be rolled out
• If the bot uses GitHub Actions, it doesn't excessively use up runners
  • Remember that this will be on all supported modules and for just about every event on an issue or pull request.

TO DECIDE

• We discussed possibly rolling this out to a single repository initially. Do we want to do that? If so, which repo?
• We discussed possibly staggering the initial closure of issues so the stalled issues aren't all closed on the same day. We need to validate with sales and marketing if that's how they'd like that handled, since any fallout will likely end up being dealt with by them.

Ways PRs can be linked to issues

• A link in the issue description to the PR
• A link in the PR description to the issue
• A comment in the PR linking to the issue
• A comment in the issue linking to the PR
• Usage of documented keywords in the PR description
• other documented ways