title: Restored using '.NETFramework,Version=v4.6.1' instead of the project target framework '.NETCoreApp,Version=v2.1'?
body: <p>I installed a Visual Studio 2019 and created a new Asp.Net core 2.1 console application project. I was trying to install NuGet package 'PDFsharp 1.50.5147' and it always gave me this warning. I have changed it to the previous versions but same things happened. </p>
  
  <p>tried to match older versions of PdfSharp with .NET version 2.1 and also tired with .NET version 2.0</p>
  
  <p><a href="https://i.stack.imgur.com/ne95f.png" rel="nofollow noreferrer">warning message </a></p>