I've given this some thought and I don't think a stable tag would improve anything over latest. What happen when a breaking change happen and we go from 1.x to 2.x ? Do we need to create a new stable-v2 tag and stop updating stable (I don't think we have the ressources to provide security update to previous major versions) ? Even without major version change in mind, the reality is that this project don't have the user feedback, metrics or ressources to absolutely guarantee that a given release is going to be "stable" compared to the previous one, beside me trying to be careful and not breaking existing setup.

I don't think I can do much more that what is already in place: releasing regularly with semantic versioning, documenting changes on release notes and warning when something breaking or unusual happen. If you want automatic updates without reading release notes or using semver tags, a stable tag that is a few week behind latest won't improve stability in any measurable way and actually negate the avantages of having versioned releases in the first place, in the same way latest does (ie you won't be able to tell what version you where running before an update caused issues and conversely you won't be able to immediately roll back to the previous working version).