Periodic job to label stale PRs python/core-workflow#93

[chetankm-cs]

This pr adds a periodic job to detect and label stale pull requests.

A pull request is considered stale if it was not updated in last 30 days and it has labels
CLA not signed/ awaiting changes.

The job will run daily at 12am and will mark pull request stale only if required.
The job is scheduled using https://github.com/agronholm/apscheduler.
Apscheduler is a pure python library and doesn't depend on any external cron/task queue for triggering the task. This helps in making the bot cross platform.

[the-knights-who-say-ni]

Hello, and thanks for your contribution!

I'm a bot set up to make sure that the project can legally accept your contribution by verifying you have signed the PSF contributor agreement (CLA).

Unfortunately we couldn't find an account corresponding to your GitHub username on bugs.python.org (b.p.o) to verify you have signed the CLA (this might be simply due to a missing "GitHub Name" entry in your b.p.o account settings). This is necessary for legal reasons before we can look at your contribution. Please follow the steps outlined in the CPython devguide to rectify this issue.

Thanks again to your contribution and we look forward to looking at it!

[codecov]

Codecov Report

Merging #67 into master will not change coverage.
The diff coverage is 100%.

@@          Coverage Diff          @@
##           master    #67   +/-   ##
=====================================
  Coverage     100%   100%           
=====================================
  Files          14     16    +2     
  Lines         876    944   +68     
  Branches       50     54    +4     
=====================================
+ Hits          876    944   +68

Impacted Files	Coverage Δ
bedevere/stale_pr.py	100% <100%> (ø)
bedevere/__main__.py	100% <100%> (ø)	⬆️
tests/test_stale_pr.py	100% <100%> (ø)

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[Mariatta]

Thanks for the work on this. Sorry we haven't been able to follow up for a few years :(
Adding and closing "stale" PRs can now be done through GitHub Actions. We have an open PR in CPython to address it (python/cpython#21247) but we haven't reached agreement on whether we want this functionality or not 🤷🏻‍♀️