title: System.ServiceModel not found in .NET Core project
body: <p>I have a .NET Core xUnit project.  I'm trying to call a WCF service from it but get the following exception:</p>
  
  <pre class="lang-none prettyprint-override"><code>System.InvalidOperationException occurred
    HResult=0x80131509
    Message=An error occurred while loading attribute 'ServiceContractAttribute' on type 'IMyContract'.  Please see InnerException for more details.
  
  Inner Exception 1:
  FileNotFoundException: Could not load file or assembly 'System.ServiceModel, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'. The system cannot find the file specified.
  </code></pre>
  
  <p>It works with a Framework 4.7 project with the same Nuget Package <code>System.ServiceModel.Http.4.3.0</code>.</p>