replace Travis CI badge with GitHub CI badge

Replaces Travis CI build status badge with the one from the GitHub workflow

README.md

@@ -1,6 +1,6 @@
 # YaCy
 [![Gitter](https://badges.gitter.im/yacy/yacy_search_server.svg)](https://gitter.im/yacy/yacy_search_server?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
-[![Build Status](https://travis-ci.org/yacy/yacy_search_server.svg?branch=master)](https://travis-ci.com/yacy/yacy_search_server)
+[![Build Status](https://github.com/yacy/yacy_search_server/actions/workflows/ant-build-selfhosted.yaml/badge.svg)](https://github.com/yacy/yacy_search_server/actions/workflows/ant-build-selfhosted.yaml)
 [![Install Link](https://img.shields.io/badge/install-stable-blue.svg)](https://yacy.net/download_installation/)
 
 [![Deploy](https://www.herokucdn.com/deploy/button.svg)](https://heroku.com/deploy)