Remove the isomorphic-fetch dependency

[gajus]

It is not the responsibility of a library to polyfill browser features.

isomorphic-fetch is now being pulled into a bundle for no good reason.

Remove the isomorphic-fetch dependency and document that user needs to polyfill Fetch if the target environment does not support Fetch API (or recommend to use https://polyfill.io/v2/docs/).

[cesarsolorzano]

@gajus Isn't this the same issue you described in #645?

[gajus]

oh, lol. I forgot about it by now.

Yes it is.

[pckhoi]

isomorphic-fetch is still being required for no good reason.

I see that recent releases of apollo-client no longer require isomorphic-fetch, yet it require apollo-link which require apollo-fetch which require isomorphic-fetch. Ultimately apollo-client still depend on isomorphic-fetch.

[gajus]

Patience.