Add privateassets=all to NS.Library.NETFramework reference

Author: natemcmaster

build/common.props

@@ -17,7 +17,7 @@
   </ItemGroup>
 
   <ItemGroup Condition="'$(TargetFrameworkIdentifier)'=='.NETFramework'">
-    <PackageReference Include="NETStandard.Library.NETFramework" Version="$(NETStandardLibraryNETFrameworkVersion)" />
+    <PackageReference Include="NETStandard.Library.NETFramework" Version="$(NETStandardLibraryNETFrameworkVersion)" PrivateAssets="All" />
   </ItemGroup>
 
 </Project>