update example code

Author: tusharpandey13

examples/cra-react-router/src/index.tsx

@@ -1,9 +1,9 @@
+import { createRoot } from "react-dom/client";
 import React, { PropsWithChildren } from 'react';
-import ReactDOM from 'react-dom';
-import App from './App';
+import App from './App.js';
 import { Auth0Provider, AppState } from '@auth0/auth0-react';
 import { BrowserRouter, useNavigate } from 'react-router-dom';
-import { Auth0ProviderOptions } from '../../../src';
+import { Auth0ProviderOptions } from '../../../src/index.js';
 
 const Auth0ProviderWithRedirectCallback = ({
   children,
@@ -12,7 +12,7 @@ const Auth0ProviderWithRedirectCallback = ({
   const navigate = useNavigate();
 
   const onRedirectCallback = (appState?: AppState) => {
-    navigate((appState && appState.returnTo) || window.location.pathname);
+    navigate((appState?.returnTo) || window.location.pathname);
   };
 
   return (
@@ -22,7 +22,9 @@ const Auth0ProviderWithRedirectCallback = ({
   );
 };
 
-ReactDOM.render(
+const root = createRoot(document.getElementById('root')!);
+
+root.render(
   <React.StrictMode>
     <BrowserRouter>
       <Auth0ProviderWithRedirectCallback
@@ -37,6 +39,5 @@ ReactDOM.render(
         <App />
       </Auth0ProviderWithRedirectCallback>
     </BrowserRouter>
-  </React.StrictMode>,
-  document.getElementById('root')
+  </React.StrictMode>
 );