title: Swashbuckle CLI cannot find XML file
body: <p>I am testing the package Swashbuckle.AspNetCore.Cli and facing an error when running 
  <code>dotnet swagger "tofile" --output "swagger.json" ".\bin\Debug\netcoreapp2.1\SwaggerTest.Api.dll" v1</code></p>
  
  <p><code>Unhandled Exception: System.IO.FileNotFoundException: Could not find file 'C:\Users\Rogier\.nuget\packages\swashbuckle.aspnetcore.cli\5.0.0-rc2\lib\netcoreapp2.0\SwaggerTest.Api.xml'.</code></p>
  
  <p>When I move the generated xml from the project folder into <code>'C:\Users\Rogier\.nuget\packages\swashbuckle.aspnetcore.cli\5.0.0-rc2\lib\netcoreapp2.0\SwaggerTest.Api.xml'</code> it works fine and swagger.json is created without any errors, but when I remove the file, the xml is missing. Is this a bug in the cli tool that the XML is not copied correctly?</p>
  
  <p>I am using:</p>
  
  <ul>
  <li><p><code>"Swashbuckle.AspNetCore.Cli" Version="5.0.0-rc2"</code></p></li>
  <li><p><code>"Swashbuckle.AspNetCore" Version="5.0.0-rc4"</code></p></li>
  <li><p><code>"Swashbuckle.AspNetCore.Annotations" Version="5.0.0-rc4"</code></p></li>
  <li><p>netcoreapp2.1</p></li>
  </ul>