Add react-native 0.57.0 transformer change

[pct]

I'd love to use react-native-stylus-transformer but due to react-native 0.57.0, it could not find styl path.

https://github.com/react-native-community/react-native-releases/blob/master/CHANGELOG.md#057

Please help!

[kristerkari]

Yeah sorry I haven't had time to update the docs to 0.57 yet. I'll try to get that done today.

In the meantime you can have a look at how the transformer changes are for 0.57 in the example apps that I have already updated to newest React Native version:
kristerkari/react-native-css-modules-stylename-example@6c5c39f#diff-41fdc10e1b5862877e4afa7e9176ee09

[pct]

Don't say sorry, your project helps a lot.

Thanks!!