update README.md

README-zh_CN.md

@@ -42,7 +42,7 @@ ReactDOM.render(<Datepicker />, mountNode);
 ### 按需使用
 
 ```jsx
-import "antd/lib/index.css"; // 只需在页面入口模块引用一次
+import 'antd/lib/index.css'; // 只需在页面入口模块引用一次
 import Datepicker from 'antd/lib/datepicker';
 ReactDOM.render(<Datepicker />, mountNode);
 ```

README.md

@@ -37,7 +37,7 @@ ReactDOM.render(<Datepicker />, mountNode);
 ### Use on demand
 
 ```jsx
-import "antd/lib/index.css"; // only need to import once in entry module
+import 'antd/lib/index.css'; // only need to import once in entry module
 import Datepicker from 'antd/lib/datepicker';
 ReactDOM.render(<Datepicker />, mountNode);
 ```