Support React 15.5 + 

Getting an error `Cannot read properties of undefined (reading 'oneOfType')`

It is due to React having changed the library for this back in 15.5: https://reactjs.org/docs/typechecking-with-proptypes.html 

```
Note:

React.PropTypes has moved into a different package since React v15.5. Please use [the prop-types library instead](https://www.npmjs.com/package/prop-types).
```