⬆️Update eslint to 9.x

[oddvernes]

This is a major update with breaking changes. Mainly we need to write a new config file with new syntax as .eslintrc.js has been deprecated

v9 Main blog post
v9 migration guide
config migration guide

[oddvernes]

This needs to wait a bit longer as none of these plugins support 9.x.x yet, and causes eslint to not be able to resolve any imports among other things

.
├─┬ eslint-plugin-import 2.29.1
│ └── ✕ unmet peer eslint@"^2 || ^3 || ^4 || ^5 || ^6 || ^7.2.0 || ^8": found 9.9.0
├─┬ eslint-plugin-jsx-a11y 6.9.0
│ └── ✕ unmet peer eslint@"^3 || ^4 || ^5 || ^6 || ^7 || ^8": found 9.9.0
├─┬ eslint-plugin-testing-library 6.3.0
│ ├── ✕ unmet peer eslint@"^7.5.0 || ^8.0.0": found 9.9.0
│ └─┬ @typescript-eslint/utils 5.62.0
│   └── ✕ unmet peer eslint@"^6.0.0 || ^7.0.0 || ^8.0.0": found 9.9.0
└─┬ eslint-plugin-react-hooks 4.6.2
  └── ✕ unmet peer eslint@"^3.0.0 || ^4.0.0 || ^5.0.0 || ^6.0.0 || ^7.0.0 || ^8.0.0-0": found 9.9.0