update readme

Author: palboss

README.md

@@ -20,6 +20,6 @@ react some little kits demo
 ### demo5 Ant Design Timeline
 - Ant Design Vertical display timeline.
 - [Timeline](https://ant.design/components/timeline/)
-### demo3 D3 react
+### demo6 D3 react
 - D3 (or D3.js) is a JavaScript library for visualizing data using web standards. D3 helps you bring data to life using SVG, Canvas and HTML.
 - [D3](https://github.com/d3/d3)