docs(examples): upgrade to React 18

Reference: https://reactjs.org/blog/2022/03/08/react-18-upgrade-guide.html

examples/create-react-app-example/package.json

@@ -3,14 +3,14 @@
   "version": "0.1.0",
   "private": true,
   "dependencies": {
-    "@testing-library/jest-dom": "^4.2.4",
-    "@testing-library/react": "^9.3.2",
-    "@testing-library/user-event": "^7.1.2",
-    "react": "^16.13.1",
-    "react-dom": "^16.13.1",
-    "react-scripts": "3.4.1",
-    "socket.io": "4",
-    "socket.io-client": "4"
+    "@testing-library/jest-dom": "^5.16.5",
+    "@testing-library/react": "^14.0.0",
+    "@testing-library/user-event": "^14.4.3",
+    "react": "^18.2.0",
+    "react-dom": "^18.2.0",
+    "react-scripts": "^5.0.1",
+    "socket.io": "^4.6.1",
+    "socket.io-client": "^4.6.1"
   },
   "scripts": {
     "start": "react-scripts start",

examples/create-react-app-example/src/index.js

@@ -1,14 +1,15 @@
 import React from 'react';
-import ReactDOM from 'react-dom';
+import { createRoot } from 'react-dom/client';
 import './index.css';
 import App from './App';
 import * as serviceWorker from './serviceWorker';
 
-ReactDOM.render(
+const container = document.getElementById('root');
+const root = createRoot(container)
+root.render(
   <React.StrictMode>
     <App />
-  </React.StrictMode>,
-  document.getElementById('root')
+  </React.StrictMode>
 );
 
 // If you want your app to work offline and load faster, you can change