Update docs on data.subscribeToMore for React 16.

[brainkim]

Trying to use data.subscribeToMore but the docs use the now deprecated componentWillReceiveProps.

A common practice is to wrap the subscribeToMore call within componentWillReceiveProps and perform the subscription after the original query has completed.

https://www.apollographql.com/docs/react/api/react-apollo.html#graphql-query-data-subscribeToMore

Might be time to update docs to use static getDerivedStateFromProps, but this would involve storing the subscription returned from subscribeToMore in React state b/c we no longer have access to the component instance.

I’m curious to know what the standard way to use subscribeToMore is in React 16.

• docs