Pass through renderProps in the Component return API

[See here](https://github.com/faceyspacey/webpack-flush-chunks/blob/master/src/createApiWithCss.js#L51). One use case for this would be passing through `nonce`s that allow for `'strict-dynamic'` CSP. That would also mean that this library doesn't have to maintain an API for script props that don't directly concern it.