Part 1 courseinfo example solution for index.js outdated

[tuome]

The example index.js solution given for the courseinfo task uses deprecated React features.

import ReactDOM from 'react-dom'
import App from './App'

ReactDOM.render(
  <App />, 
  document.getElementById('root')
)

should be

import ReactDOM from 'react-dom/client'
import App from './App'

ReactDOM.createRoot(document.getElementById('root')).render(<App />)