Add download statistics of releases.

Add download statistics of releases.
diff --git a/README.md b/README.md
index d55a717..6bc2222 100644
--- a/README.md
+++ b/README.md
@@ -1,8 +1,8 @@
-# RocketMQ-Client-CPP

+# RocketMQ Client CPP

 [![License](https://img.shields.io/badge/license-Apache%202-4EB1BA.svg)](https://www.apache.org/licenses/LICENSE-2.0.html)

 [![Build Status](https://app.travis-ci.com/apache/rocketmq-client-cpp.svg?branch=master)](https://app.travis-ci.com/apache/rocketmq-client-cpp)

 [![CodeCov](https://codecov.io/gh/apache/rocketmq-client-cpp/branch/master/graph/badge.svg)](https://codecov.io/gh/apache/rocketmq-client-cpp)

-[![GitHub release](https://img.shields.io/badge/release-download-default.svg)](https://github.com/apache/rocketmq-client-cpp/releases)

+[![GitHub release](https://img.shields.io/github/downloads/apache/rocketmq-client-cpp/total)](https://github.com/apache/rocketmq-client-cpp/releases)

 ![Twitter Follow](https://img.shields.io/twitter/follow/ApacheRocketMQ?style=social)

 

 RocketMQ-Client-CPP is the C/C++ client of Apache RocketMQ, a distributed messaging and streaming platform with low latency, high performance and reliability, trillion-level capacity and flexible scalability.