Check for a "go-ipfs" property in the parent project

[olizilla]

From the docs, I assume I should be able to set a go-ipfs property in the package.json of a project that depends on go-ipfs-dep, but from the code, it looks like it will always check for a go-ipfs property on it's own package.json and nowhere else.

pkg is this projects package.json
https://github.com/ipfs/npm-go-ipfs-dep/blob/363d0273f3d34fb3038dcde66e79dffc9b3a4bdf/src/index.js#L28

and later we check it for a go-ipfs property
https://github.com/ipfs/npm-go-ipfs-dep/blob/363d0273f3d34fb3038dcde66e79dffc9b3a4bdf/src/index.js#L62

I'm assuming that's a bug, as I can't think of a use case for needing to set that for this package.