Fix CI badges in the README (#47)

Author: DilumAluthge

README.md

@@ -1,8 +1,7 @@
 # GitCommand
 
-[![Build Status](https://travis-ci.com/bcbi/GitCommand.jl.svg?branch=master)](https://travis-ci.com/bcbi/GitCommand.jl)
-[![Cirrus CI - Base Branch Build Status](https://img.shields.io/cirrus/github/bcbi/GitCommand.jl)](https://cirrus-ci.com/github/bcbi/GitCommand.jl)
-[![Codecov](https://codecov.io/gh/bcbi/GitCommand.jl/branch/master/graph/badge.svg)](https://codecov.io/gh/bcbi/GitCommand.jl)
+[![CI](https://github.com/JuliaVersionControl/GitCommand.jl/actions/workflows/ci.yml/badge.svg)](https://github.com/JuliaVersionControl/GitCommand.jl/actions/workflows/ci.yml)
+[![codecov](https://codecov.io/gh/JuliaVersionControl/GitCommand.jl/branch/master/graph/badge.svg?token=cdXpiH0OJ3)](https://codecov.io/gh/JuliaVersionControl/GitCommand.jl)
 
 GitCommand allows you to use command-line Git in your Julia packages. You do
 not need to have Git installed on your computer, and neither do the users of