feat: make debug.deep more usable (#40)

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### Summary

Make `debug.deep` more usable by allowing it to print arbitrary JSON (and actually any) files. This proves handy when we want to debug async component which we want to snapshot after async operations:

```jsx
const { toJSON, getByName } = render(
  <Button onPress={jest.fn} text="Press me" />
);
fireEvent.press(getByName('TouchableOpacity'));
await flushMicrotasksQueue();

debug.deep(toJSON());
```

### Test plan

added one

README.md

@@ -295,6 +295,7 @@ There's also `debug.deep` that renders deeply to stdout.
 import { debug } from 'react-native-testing-library';
 
 debug.deep(<Component />);
+debug.deep(toJSON(), 'actually debug JSON too'); // useful when Component state changes
 ```
 
 logs: