docs: add Ant Design logo to README

Author: afc163

README.md

@@ -1,6 +1,7 @@
 <div align="center">
   <h1>@rc-component/dropdown</h1>
   <p><sub>Part of the Ant Design ecosystem.</sub></p>
+  <img alt="Ant Design" height="32" src="https://gw.alipayobjects.com/zos/rmsportal/KDpgvguMpGfqaHPjicRK.svg" />
   <p>🔽 A trigger-driven dropdown component for React.</p>
 </div>
 

README.zh-CN.md

@@ -1,6 +1,7 @@
 <div align="center">
   <h1>@rc-component/dropdown</h1>
   <p><sub>Ant Design 生态的一部分。</sub></p>
+  <img alt="Ant Design" height="32" src="https://gw.alipayobjects.com/zos/rmsportal/KDpgvguMpGfqaHPjicRK.svg" />
   <p>⬇️ React 下拉菜单基础组件，基于 trigger 和 menu 能力构建。</p>
 </div>