Update build status badge

Author: iivanou

README.md

@@ -1,7 +1,7 @@
 # ReportPortal python client
 
 [![PyPI](https://img.shields.io/pypi/v/reportportal-client.svg?maxAge=259200)](https://pypi.python.org/pypi/reportportal-client)
-[![Build Status](https://travis-ci.org/reportportal/client-Python.svg?branch=master)](https://travis-ci.org/reportportal/client-Python)
+[![Build Status](https://github.com/reportportal/client-Python/actions/workflows/tests.yml/badge.svg)](https://github.com/reportportal/client-Python/actions/workflows/tests.yml)
 [![codecov.io](https://codecov.io/gh/reportportal/client-Python/branch/master/graph/badge.svg)](https://codecov.io/gh/reportportal/client-Python)
 
 Library used only for implementors of custom listeners for ReportPortal