Update peerDependency on React

[heyimalex]

Currently produces a warning with v16. Pretty sure there weren't any breaking changes wrt react-refetch (at least I haven't experienced anything obvious) so it should be safe to bump.

[ryanbrainard]

Fixed in e812392 and pre-released in v1.0.3-0. This still needs to be tested, so this is just a pre-release, but wanted to get something out there so folks and kick the tires.