[core] Coerce semver to allow prereleases of React

[bjoerge]

Currently our React version check disallows prereleases of React, which I don't think there are any good reasons to do. This coerces the semver before calling the satisifes check.

For reference

semver.satisfies(semver.coerce('16.8.0-alpha.0'), '^16.2') // true
semver.satisfies(semver.coerce('16.6'), '^16.2') // true
semver.satisfies(semver.coerce('16.1'), '^16.2') // false
semver.satisfies(semver.coerce('17.0.0'), '^16.2') // false