chore: adding stale config

[callum-tait-pbx]

Relates to #443

This is a config for https://github.com/apps/stale. We have many many many many issues in the backlog where people have raised them and never returned. We need a bot to prune the issues over time to keep the repository maintained.

@mumoshu I think this is worth having, please read through the config as I have just put in some basic boilerplate and request any changes e.g. more / different labels. Additionally, any issues we wish to keep need some labels applied to them to stop the bot closing them before this is merged. We have a number of old tickets which are legitimate features worth keeping.

This requires the stale app installed into the repo to work https://github.com/apps/stale

If merged we will need to make use of labels going forward.

[mumoshu]

LGTM. Thanks a lot for proposing it and composing the config ☺️

[mumoshu]

Installed the Stale app onto this repo. Are there any remaining tasks we need to do about this @callum-tait-pbx ?

[callum-tait-pbx]

I can see the bot is already starting to tag things as stale, nice! For anything we wish to keep (PR or issue wise) we need to attach at least one of the exemptLabels to the PR / issue. A maintainer will need to go through the PRs and issues and associated the relevant exempt labels to each PR / issue to prevent the bot closing the PR / issue. Additionally the stale label needs removing from any issues / PRs that have already been tagged as stale that we wish to keep.

#144 this is a good example of a legititmate issue that has been marked as stale but we would want to keep around (and do at some point!)

I've included a generic pinned label for PRs / issues we wish to keep that don't fit into any specific category.

Feel free to add, remove or change the labels there, it was just a first stab of labels that are fairly popular.

CC @mumoshu

EDIT

Given there is a date wher the bot will start killing issues and PRs this needs doing sooner rather than later