[Request] Update repo with eslint v9 flat config format

[Stanzilla]

Hey, eslint v8 is deprecated and should no longer be used, along with the old eslintrc format. It would be great if this repo was upgraded to showcase an example on how to do eslint v9 the best way in a monorepo with nx, hopefully with a installable eslint-config package instead of the previous tools approach.

[okuzava]

not the best example, but a good candidate to check: https://github.com/nrwl/nx-recipes/tree/main/react-monorepo