ESLint 9

[leighmacdonald]

Migrate from ESLint 8->9. Unfortunately this uses a whole new config format because javascript libs do be like that.

This will include fixing up the included plugins as well.

[Gcommer]

Heyo, random driveby: I took a quick look at this, seems this is currently blocked on jsx-eslint/eslint-plugin-react#3699

Also typescript-eslint has v9 support, but only on alpha releases, which you may not be comfortable with: typescript-eslint/typescript-eslint#8211

[leighmacdonald]

Hey, Yeah i've had some reasonable success with the alpha version in a smaller, very simple, project with a similar stack i work on. Its, however, probably worth waiting another month or so at least before tackling this on here. The amount of plugins that fully supported 9 was still a bit hit or miss, and i am using a few more here, though i did get to a pretty reasonable place after a bit of struggle, so its pretty close for sure.