knip: Automatic plugin enabling fails while in a monorepo

Hello and thanks for the awesome tool!

Currently, knip appears to work by examining the closest package.json file for an eslint dependency. However, this algorithm will fail in a monorepo that looks like this:

my-monorepo/
├── package.json (contains development deps for every subpackage)
└── packages/
    └── foo
        └── package.json (contains only production deps, for the purposes of publishing to npm)

AFAIK, it is common in monorepos to not repeat the ESLint dep for N subpackages. Instead, the ESLint dep is declared once in the root package.json file.

Currently, it is possible to work around this problem by creating a knip.json file for every subpackage in the repo, containing ignore: [".eslintrc.cjs"]. However, this is of course quite cumbersome. It would be nice to update the algorithm such that it can properly detect that ESLint is a dep while inside of a monorepo.

Finally, I’ll note that the same problem applies to the Jest plugin, the Remark plugin, and so on.