Exit animations support

### Before submitting a new issue

- [x] I tested using the latest version of the library, as the bug might be already fixed.
- [x] I tested using a [supported version](https://github.com/reactwg/react-native-releases/blob/main/docs/support.md) of react native.
- [x] I checked for possible duplicate issues, with possible answers.

### Bug summary

I saw in the documentation that this library also supports exit animations, but I couldn't find any instructions related to exit animations in the documentation. How can I implement this?

### Library version

0.7.2

### Environment info

```shell
.
```

### Steps to reproduce

how?

### Reproducible example repository

none