Add types to package.json exports

[aautem]

My Vite project is unable to resolve the types for this plugin:

Could not find a declaration file for module 'vite-plugin-multiple'.
'/node_modules/vite-plugin-multiple/index.js' implicitly has an 'any' type.
There are types at '/node_modules/vite-plugin-multiple/types/index.d.ts',
but this result could not be resolved when respecting package.json "exports".
The 'vite-plugin-multiple' library may need to update its package.json or typings.

This fix explicitly exposes the types file in the import and require export objects.

Additional info:
https://github.com/arethetypeswrong/arethetypeswrong.github.io/blob/main/docs/problems/UntypedResolution.md
https://github.com/arethetypeswrong/arethetypeswrong.github.io/blob/main/docs/problems/FalseCJS.md

[lesmoutonssauvages]

@caoxiemeihao I have the same problem and hope this gets merged.

Thanks @aautem

[carmelocatalfamo]

Same problem, news on this?