Remove Fossa, replace CI badge in README (#50)

Author: martialonline

.github/workflows/fossa.yml

@@ -1,5 +1,5 @@
 
-[![Build Status](https://travis-ci.org/nginxinc/nginx-plus-go-client.svg?branch=master)](https://travis-ci.org/nginxinc/nginx-plus-go-client)  [![License](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](https://opensource.org/licenses/Apache-2.0)  [![Go Report Card](https://goreportcard.com/badge/github.com/nginxinc/nginx-plus-go-client)](https://goreportcard.com/report/github.com/nginxinc/nginx-plus-go-client)
+[![Continuous Integration](https://github.com/nginxinc/nginx-plus-go-client/workflows/Continuous%20Integration/badge.svg)](https://github.com/nginxinc/nginx-plus-go-client/actions)  [![License](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](https://opensource.org/licenses/Apache-2.0)  [![Go Report Card](https://goreportcard.com/badge/github.com/nginxinc/nginx-plus-go-client)](https://goreportcard.com/report/github.com/nginxinc/nginx-plus-go-client)
 
 # NGINX Plus Go Client