Include working example

[r0hin]

Feature Request

It would be useful to include a working expo example to test out and play around with. Something like a quick app.tsx file with basic preset tabs would work.

Why it is needed

• helps new users understand how it's used
• quickly proves if the library works or not

Possible implementation

• add a expo working example inside the examples folder

This would help me a lot as my previous issue https://github.com/gorhom/react-native-animated-tabbar/issues/100 wasn't resolved.

Edit: forgot to mention expo version.