[fix] wrong pointer to travis and codecov

Author: tswsxk

README.md

@@ -1,8 +1,8 @@
 # EduNLP
 
 [![PyPI](https://img.shields.io/pypi/v/EduNLP.svg)](https://pypi.python.org/pypi/EduNLP)
-[![Build Status](https://www.travis-ci.org/bigdata-ustc/EduNLP.svg?branch=main)](https://www.travis-ci.org/bigdata-ustc/EduNLP)
-[![codecov](https://codecov.io/gh/bigdata-ustc/EduNLP/branch/main/graph/badge.svg?token=B7gscOGQLD)](https://codecov.io/gh/bigdata-ustc/EduNLP)
+[![Build Status](https://www.travis-ci.org/bigdata-ustc/EduNLP.svg?branch=master)](https://www.travis-ci.org/bigdata-ustc/EduNLP)
+[![codecov](https://codecov.io/gh/bigdata-ustc/EduNLP/branch/master/graph/badge.svg?token=B7gscOGQLD)](https://codecov.io/gh/bigdata-ustc/EduNLP)
 [![Download](https://img.shields.io/pypi/dm/EduNLP.svg?style=flat)](https://pypi.python.org/pypi/EduNLP)
 [![License](https://img.shields.io/github/license/bigdata-ustc/EduNLP)](LICENSE)