[feat]update coverpage

_coverpage.md

 <p align="center">
-<img src="https://my-blog-to-use.oss-cn-beijing.aliyuncs.com/2019-3logo-透明.png" width=""/>
+<img src="./media/pictures/logo.png" width="200" height="200"/>
 </p>
 
+
 <h1 align="center">Java 学习/面试指南</h1>
 
 [常用资源](https://shimo.im/docs/MuiACIg1HlYfVxrj/)
 [GitHub](<https://github.com/Snailclimb/JavaGuide>)
 [开始阅读](#java)
 
-![](./media/pictures/rostyslav-savchyn-5joK905gcGc-unsplash.jpg)
-