Switch to prop-types

[JulianKingman]

Currently, using the latest react (16) gives various PropTypes errors (as PropTypes was removed). This should update to use the prop-types package. I can do a PR if you like.

[goshacmd]

I've just released 1.1.0 with the fix for that, thanks to @tpisto

[sadlerjw]

@goshakkk The Yarn package manager does some caching on their own infrastructure, so this fix hasn't made it out into any projects pulling down this project via Yarn. (Yarn has resolved v1.1.0 of this package to https://registry.yarnpkg.com/react-native-navigation-experimental-compat/-/react-native-navigation-experimental-compat-1.1.0.tgz#5d819fe0266d5af0d91e67fed8aa47fc069b6fe3, which is the old version.)
Could you please add version tags to this repo and bump the version number, so that Yarn projects can get these changes? Thanks!