update maven link

README.md

@@ -4,7 +4,7 @@
 
 [![Build Status](https://travis-ci.org/alibaba/arthas.svg?branch=master)](https://travis-ci.org/alibaba/arthas)
 [![codecov](https://codecov.io/gh/alibaba/arthas/branch/master/graph/badge.svg)](https://codecov.io/gh/alibaba/arthas)
-![maven](https://img.shields.io/maven-central/v/com.taobao.arthas/arthas-packaging.svg)
+[![maven](https://img.shields.io/maven-central/v/com.taobao.arthas/arthas-packaging.svg)](https://search.maven.org/search?q=g:com.taobao.arthas)
 ![license](https://img.shields.io/github/license/alibaba/arthas.svg)
 [![Average time to resolve an issue](http://isitmaintained.com/badge/resolution/alibaba/arthas.svg)](http://isitmaintained.com/project/alibaba/arthas "Average time to resolve an issue")
 [![Percentage of issues still open](http://isitmaintained.com/badge/open/alibaba/arthas.svg)](http://isitmaintained.com/project/alibaba/arthas "Percentage of issues still open")