updated build props for icon

Author: varndellwagglebee

Directory.Build.props

@@ -36,6 +36,7 @@
 
   <!-- Pull README & LICENSE into the package root -->
   <ItemGroup Condition="'$(IsPackable)' == 'true'">
+    <None Include="..\..\assets\icon.png" Pack="true" Visible="false" PackagePath="/" />
     <None Include="$(MSBuildThisFileDirectory)README.md"
           Pack="true"
           PackagePath="\"