Update README.md

Author: binarywang

README.md

@@ -1,6 +1,6 @@
 Java实现的各种随机测试数据生成器，包括身份证号码，银行卡号，姓名，手机号，电子邮箱地址和生成insert sql参数列表字符串等。
 
-[![Build Status](https://travis-ci.org/binarywang/java-testdata-generator.svg?branch=develop)](https://travis-ci.org/binarywang/java-testdata-generator)
+[![Build Status](https://travis-ci.org/binarywang/java-testdata-generator.svg?branch=master)](https://travis-ci.org/binarywang/java-testdata-generator)
 ![Maven Central](https://maven-badges.herokuapp.com/maven-central/com.github.binarywang/java-testdata-generator/badge.svg)