Close stale PRs with no CLA signature

[hugovk]

The short story

We used to close stale PRs that did not have the CLA signed.

We no longer have that with the new CLA bot.

Let's reimplement it.

Long version

In #93 we used a GitHub action to label PRs which have had no activity for 30 days with a stale label.

• If the PR had the CLA not signed label, it would be auto-closed after 14 days.

• If the PR had the CLA signed label, it would not be auto-closed.

We're now using a CLA bot that uses a status check and does not add/remove labels, so the label-specific stuff was removed in python/cpython#91429; it now only applies the stale label and cannot close old PRs.

How can we reimplement this?

https://github.com/actions/stale does not see PR status checks. Can the CLA bot be updated to add/remove labels?

[arhadthedev]

I think it's better to hook bedevere on CLA bot status change and let it do the job (webhook docs). Extra labels were creating a visual clutter, as for me.