Update README.md

Author: wxnet2013

README.md

@@ -1,15 +1,15 @@
 简体中文 | [English](README-en_US.md)
 # rxloop [![NPM version][npm-image]][npm-url] [![npm download][download-image]][download-url] [![Build Status][build-status-image]][build-status-url] [![codecov status][codecov-image]][codecov-url] [![license][license-image]][license-url]
 
-[npm-image]: https://img.shields.io/npm/v/@rxloop/core.svg?style=shield
+[npm-image]: https://img.shields.io/npm/v/@rxloop/core.svg?style=shield&colorB=brightgreen
 [npm-url]: https://npmjs.org/package/@rxloop/core
-[download-image]: https://img.shields.io/npm/dm/@rxloop/core.svg?style=shield
+[download-image]: https://img.shields.io/npm/dm/@rxloop/core.svg?style=shield&colorB=brightgreen
 [download-url]: https://npmjs.org/package/@rxloop/core
-[build-status-image]: https://circleci.com/gh/TalkingData/rxloop/tree/master.png?style=shield
+[build-status-image]: https://circleci.com/gh/TalkingData/rxloop/tree/master.png?style=shield&colorB=brightgreen
 [build-status-url]: https://circleci.com/gh/TalkingData/rxloop
-[codecov-image]: https://img.shields.io/codecov/c/github/TalkingData/rxloop/master.svg?style=shield
+[codecov-image]: https://img.shields.io/codecov/c/github/TalkingData/rxloop/master.svg?style=shield&colorB=brightgreen
 [codecov-url]: https://codecov.io/github/TalkingData/rxloop?branch=master
-[license-image]: https://img.shields.io/npm/l/@rxloop/core.svg
+[license-image]: https://img.shields.io/npm/l/@rxloop/core.svg?style=shield&colorB=brightgreen
 [license-url]: https://github.com/TalkingData/rxloop/blob/master/LICENSE