Provide a way to add dependencies to the generated package.json

[j2ghz]

💡 Feature description

There should be some way of specifying a list of dependencies that should be included when wasm-pack generates package.json.

💻 Basic example

The public interface of my wasm crate references HidDevice, which is only defined in @types/w3c-web-hid. That means the users of my crate will only see unresolved references (Cannot find name 'HIDDevice'.ts(2304)), unless they install the types themselves. The best practice is to include @types/* dependencies, if they appear in the public interface, but there's no easy way to do that with wasm-pack.
A workarounds is to do text or json manipulation after each wasm-pack build, but that is not great dx.