This bumps all eslint packages, ensuring compatibility with TypeScript 5.7.3. Previously, the following would be thrown:
```bash
WARNING: You are currently running a version of TypeScript which is not officially supported by @typescript-eslint/typescript-estree.
You may find that it works just fine, or you may not.
SUPPORTED TYPESCRIPT VERSIONS: >=4.7.4 <5.7.0
YOUR TYPESCRIPT VERSION: 5.7.3
Please only submit bug reports when using the officially supported version
```
This [might have caused errors during linting](https://payloadcms.slack.com/archives/C04H7CQ615K/p1741707183505329?thread_ts=1741707036.030089&cid=C04H7CQ615K).
`payload` lint before: ✖ 380 problems (9 errors, 371 warnings)
`payload` lint after: ✖ 381 problems (9 errors, 372 warnings)
`ui` lint before: ✖ 154 problems (12 errors, 142 warnings)
`ui` lint after: ✖ 267 problems (12 errors, 255 warnings)
The additional warnings in `ui` come from the new `@eslint-react/no-use-context` and `@eslint-react/no-context-provider` rules which are good to have in React 19.
So `_Upload` becomes `UploadComponent` which doesnt break the naming
convention of react components and **we no longer export these internal
components**
- Upgrades eslint from v8 to v9
- Upgrades all other eslint packages. We will have to do a new
full-project lint, as new rules have been added
- Upgrades husky from v8 to v9
- Upgrades lint-staged from v14 to v15
- Moves the old .eslintrc.cjs file format to the new eslint.config.js
flat file format.
Previously, we were very specific regarding which rules are applied to
which files. Now that `extends` is no longer a thing, I have to use
deepMerge & imports instead.
This is rather uncommon and is not a documented pattern - e.g.
typescript-eslint docs want us to add the default typescript-eslint
rules to the top-level & then disable it in files using the
disable-typechecked config.
However, I hate this opt-out approach. The way I did it here adds a lot
of clarity as to which rules are applied to which files, and is pretty
easy to read. Much less black magic
## .eslintignore
These files are no longer supported (see
https://eslint.org/docs/latest/use/configure/migration-guide#ignoring-files).
I moved the entries to the ignores property in the eslint config. => one
less file in each package folder!
