bootstrap: Fix "ReactDOM.render is deprecated since React 18.0.0" lint error

After bumping to React 18 linter was outputting following error: "ReactDOM.render is deprecated since React 18.0.0, use createRoot instead, see https://reactjs.org/link/switch-to-createroot"
This fixes the problem.

src/bootstrap.js

@@ -1,7 +1,9 @@
 import React from 'react';
 
-import ReactDOM from 'react-dom';
+import { createRoot } from 'react-dom/client';
 
 import ImageBuilder from './AppEntry';
 
-ReactDOM.render(<ImageBuilder />, document.getElementById('root'));
+const root = createRoot(document.getElementById('root'));
+
+root.render(<ImageBuilder />);