Update README.md (#318)

Author: Yang-33

README.md

@@ -1,6 +1,6 @@
 # LINE Messaging API SDK for Ruby
 
-[![Gem-version](https://img.shields.io/gem/v/line-bot-api.svg)](https://rubygems.org/gems/line-bot-api) [![Build Status](https://travis-ci.org/line/line-bot-sdk-ruby.svg?branch=master)](https://travis-ci.org/line/line-bot-sdk-ruby)
+[![Gem-version](https://img.shields.io/gem/v/line-bot-api.svg)](https://rubygems.org/gems/line-bot-api)
 
 
 ## Introduction