Copy Xamarin.Mac.ObjCBinding.CSharp.props to output dir

This is needed from VS because we grab all the files from the output directory to generate the msbuild.zip that contains all the targets and props

msbuild/Xamarin.Mac.Tasks/Xamarin.Mac.Tasks.csproj

@@ -107,6 +107,9 @@
     <None Include="Xamarin.Mac.ObjCBinding.CSharp.targets">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </None>
+    <None Include="Xamarin.Mac.ObjCBinding.CSharp.props">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </None>
     <None Include="Xamarin.Mac.AppExtension.Common.props">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </None>