Update badges

Author: YingboMa

README.md

@@ -1,8 +1,7 @@
 # ModelingToolkit.jl
 
-[![Build Status](https://travis-ci.com/SciML/ModelingToolkit.jl.svg?branch=master)](https://travis-ci.com/SciML/ModelingToolkit.jl)
-[![Coverage Status](https://coveralls.io/repos/SciML/ModelingToolkit.jl/badge.svg?branch=master&service=github)](https://coveralls.io/github/JuliaDiffEq/ModelingToolkit.jl?branch=master)
-[![codecov.io](http://codecov.io/github/SciML/ModelingToolkit.jl/coverage.svg?branch=master)](http://codecov.io/github/SciML/ModelingToolkit.jl?branch=master)
+[![Github Action CI](https://github.com/SciML/ModelingToolkit.jl/workflows/CI/badge.svg)](https://github.com/SciML/ModelingToolkit.jl/actions)
+[![Coverage Status](https://coveralls.io/repos/github/SciML/ModelingToolkit.jl/badge.svg?branch=master)](https://coveralls.io/github/SciML/ModelingToolkit.jl?branch=master)
 [![Stable](https://img.shields.io/badge/docs-stable-blue.svg)](http://mtk.sciml.ai/stable/)
 [![Dev](https://img.shields.io/badge/docs-dev-blue.svg)](http://mtk.sciml.ai/dev/)