Update README.md

Author: wenbinf

README.md

@@ -1,6 +1,6 @@
 # Podcast API Python Library
 
-[![Build Status](https://travis-ci.com/ListenNotes/python-api-python.svg?branch=master)](https://travis-ci.com/ListenNotes/python-api-python)
+[![Build Status](https://travis-ci.com/ListenNotes/python-api-python.svg?branch=main)](https://travis-ci.com/ListenNotes/python-api-python)
 
 The Podcast API Python library provides convenient access to the [Listen Notes Podcast API](https://www.listennotes.com/api/) from
 applications written in the Python language.
@@ -62,4 +62,4 @@ the sort of error that occurred.
 
 All exception classes can be found in [this file](https://github.com/ListenNotes/podcast-api-python/blob/main/listennotes/errors.py).
 
-And you can see some sample code [here](https://github.com/ListenNotes/podcast-api-python/blob/main/examples/sample.py#L17).
+And you can see some sample code [here](https://github.com/ListenNotes/podcast-api-python/blob/main/examples/sample.py#L17).