Revisit dependency pinning

Created by: iansu

Pinning all of our dependencies causes issues with the preflight check whenever a new version of a nested dependency is released. babel-jest is one example of this. When a new version is released and used by another dependency the preflight check fails until we update our version to match.

We should consider unpinning certain dependencies like babel-jest and updating the preflight check to work with carrot versions like ^24.7.1. It currently only works with exact version numbers.