RFC: Add configuration for Probot Stale

[nijel]

See https://github.com/probot/stale/

We have quite some pull requests which did not receive attention for quite some time and are not ready to be merged. This enables Probot Stale to label those as wontfix after 60 days and close them after additional 7 days without activity.

I think it's better to having a bot do the work because it, to some degree, is less personal and it can avoid bad feelings from the contributors as it's bureaucracy that closed your pull request.

[codecov]

Codecov Report

Merging #13380 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master   #13380   +/-   ##
=======================================
  Coverage   54.56%   54.56%           
=======================================
  Files         467      467           
  Lines       70464    70464           
=======================================
  Hits        38447    38447           
  Misses      32017    32017

[MauricioFauth]

I think it's a good option. If there is no activity with these deadlines, it is better to close the PR.

[ibennetch]

I somewhat rather disagree; it's easy for us to accidentally ignore a pull request or assume someone else is looking at it; closing such requests automatically may cause us to inadvertently ignore someone's work. However, I do understand that it can be seen as better to be rejected by a bot than a human. I'm not sure I have a better idea, but I'm concerned that automating rejections may cause problems.

[nijel]

It first adds comment and if nothing happens for additional week, the issue is closed. The thresholds can be configured.

You can see example interaction here: WeblateOrg/weblate#1128 (comment)

[udan11]

I am ok with this.

[nijel]

Merged, I think it is really good to have something pushing on stale pull requests as otherwise they will stay not handled for really long.