Update Readme.md

Author: swmal

Readme.md

@@ -1,6 +1,7 @@
 ![Nuget](https://img.shields.io/nuget/v/epplus)
  [![Download EPPlus from nuget](https://img.shields.io/nuget/dt/epplus?label=Nuget%20downloads)](https://www.nuget.org/packages/EPPlus/)
 [![Build status](https://ci.appveyor.com/api/projects/status/qw2hvjk7yfxv7vrv?svg=true)](https://ci.appveyor.com/project/EPPlusSoftware/epplus8)
+[![Code Scanning](https://github.com/EPPlusSoftware/EPPlus/actions/workflows/code-scanning.yml/badge.svg)](https://github.com/EPPlusSoftware/EPPlus/actions/workflows/code-scanning.yml)
 # EPPlus 8
 
 ## License