update readme

Author: cbeck88

README.md

@@ -1,7 +1,7 @@
 # visit_struct
 
-[![Build Status](https://travis-ci.org/cbeck88/visit_struct.svg?branch=master)](http://travis-ci.org/cbeck88/visit_struct)
-[![Appveyor status](https://ci.appveyor.com/api/projects/status/6ksqg7es938cttn2/branch/master?svg=true)](https://ci.appveyor.com/project/cbeck88/visit_struct)
+[![Build Status](https://github.com/cbeck88/visit_struct/actions/workflows/ci.yml/badge.svg)](http://travis-ci.org/cbeck88/visit_struct)
+
 [![Boost licensed](https://img.shields.io/badge/license-Boost-blue.svg)](./LICENSE)
 
 A header-only library providing **structure visitors** for C++11 and C++14.