Snack Expo Example

[louisiscoding]

Hi,

That would be quite practical to have some of the example in a Snack Expo
(https://snack.expo.io/) so we can give it a try painlessly.

Thanks for your work.

[peterpme]

@LouisJS sounds like a great first PR!

[top-kat]

You may also want to put in the doc whenever react-native-phone-input is compatible with a managed expo project. Actually it seems it's not