prop-types are not actually removed in production

[nolanlawson]

Currently this package is using babel-plugin-transform-react-remove-prop-types but it's not actually removing prop-types because the usage of prop-types is too subtle for the Babel transform to figure out.

Also, our usage precludes the possibility of library users from removing it themselves using this same Babel plugin.

You can reproduce this issue by running:

yarn build

Then:

egrep -r '(prop-types|shared-props)' dist dist-es

Then you'll see that there are several files importing these modules, even in the production build.