Update Directory.Build.props

Author: SimonCropp

Directory.Build.props

@@ -19,7 +19,7 @@
   </PropertyGroup>
   <ItemGroup>
     <PackageReference
-     Condition="$(MSBuildProjectName.EndsWith('Tests'))"
+     Condition="!$(MSBuildProjectName.EndsWith('Tests'))"
      Include="Microsoft.SourceLink.GitHub" Version="1.1.1" PrivateAssets="All"/>
   </ItemGroup>
 </Project>