fix: React is not defined

src/app.tsx

@@ -5,8 +5,10 @@ import type { Settings as LayoutSettings } from '@ant-design/pro-components';
 import { SettingDrawer } from '@ant-design/pro-components';
 import type { RunTimeLayoutConfig } from '@umijs/max';
 import { history, Link } from '@umijs/max';
+import React from 'react';
 import defaultSettings from '../config/defaultSettings';
 import { errorConfig } from './requestErrorConfig';
+
 const isDev = process.env.NODE_ENV === 'development';
 const loginPath = '/user/login';
 

src/components/RightContent/index.tsx

@@ -1,5 +1,6 @@
 import { QuestionCircleOutlined } from '@ant-design/icons';
 import { SelectLang as UmiSelectLang } from '@umijs/max';
+import React from 'react';
 
 export type SiderTheme = 'light' | 'dark';