Add a working example in docs as app is not working

[ashishpatel1992]

Please add a working example in docs.
It is crashing with error

ERROR  TypeError: undefined is not an object (evaluating '_$$_REQUIRE(_dependencyMap[2], "react-native-piano").MidiNumbers.fromNote')
ERROR  Invariant Violation: Module AppRegistry is not a registered callable module (calling runApplication). A frequent cause of the error is that the application entry file path is incorrect.

App.tsx

import React from 'react';
// @ts-ignore
import {Piano, KeyboardShortcuts, MidiNumbers} from 'react-native-piano';
// @ts-ignore
import type {Node} from 'react';

const noteRange = {
  first: MidiNumbers.fromNote('c3'),
  last: MidiNumbers.fromNote('f5'),
};

const App: () => Node = () => {
  return <Piano noteRange={noteRange} />;
};
export default App;