`package.json` lookup should be from ESLint cwd

[privatenumber]

ESLint supports setting the cwd.

However, the getPackageJson function looks up using process.cwd().

[privatenumber]

Since creating dynamic configurations are not possible, I would recommend moving type look up to a per-rule basis. That way, ESLint's cwd is available and would yield accurate results for monorepos that contain mixed types.

Also, seems like the env configurations are pretty much identical to ESLint's builtin environments. I think this plugin could have a "smarter" rule that detects whether a CommonJS variable is used in a Module.