Update Readme.md

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Readme.md

@@ -2,6 +2,7 @@ Open Asset Import Library (assimp)
 ==================================
 A library to import and export various 3d-model-formats including scene-post-processing to generate missing render data.
 ### Current project status ###
+![C/C++ CI](https://github.com/assimp/assimp/workflows/C/C++%20CI/badge.svg)
 [![Linux Build Status](https://travis-ci.org/assimp/assimp.svg)](https://travis-ci.org/assimp/assimp)
 [![Windows Build Status](https://ci.appveyor.com/api/projects/status/tmo433wax6u6cjp4?svg=true)](https://ci.appveyor.com/project/kimkulling/assimp)
 <a href="https://scan.coverity.com/projects/5607">