Delete Travis config and badge

Author: marcphilipp

.travis.settings.xml

@@ -6,4 +6,4 @@ For more information, please visit:
 * [Download and Install guide](https://github.com/junit-team/junit4/wiki/Download-and-Install)
 * [Getting Started](https://github.com/junit-team/junit4/wiki/Getting-started)
 
-[![Build Status](https://travis-ci.org/junit-team/junit4.svg?branch=main)](https://travis-ci.org/junit-team/junit4)
+[![CI Status](https://github.com/junit-team/junit4/workflows/CI/badge.svg)](https://github.com/junit-team/junit4/actions)