CI: Update badges

README.md

@@ -1,6 +1,6 @@
 # Simple-RTMP-Server
 
-[![CircleCI](https://circleci.com/gh/ossrs/srs/tree/2.0release.svg?style=svg&circle-token=1ef1d5b5b0cde6c8c282ed856a18199f9e8f85a9)](https://circleci.com/gh/ossrs/srs/tree/2.0release)
+[![CircleCI](https://circleci.com/gh/ossrs/srs/tree/master.svg?style=svg&circle-token=1ef1d5b5b0cde6c8c282ed856a18199f9e8f85a9)](https://circleci.com/gh/ossrs/srs/tree/master)
 [![Wechat](https://cloud.githubusercontent.com/assets/2777660/22814959/c51cbe72-ef92-11e6-81cc-32b657b285d5.png)](https://github.com/ossrs/srs/wiki/v1_CN_Contact#wechat)
 [<img width="52" alt="Skype" src="https://cloud.githubusercontent.com/assets/2777660/24329166/3821a328-1230-11e7-844a-506a5d17dd3d.png">](https://github.com/ossrs/srs/wiki/v1_EN_Contact#skype-or-gitter)