I am using VS 2017. I created a class library project in .net standard. I then added connected service using a URL (project -> right click -> add -> connected service). When the service is detected, I used default settings and clicked finish.
Unable to generate deps.json, it may have been already generated. You can specify the "-d" option before the tool name for diagnostic output (for example, "dotnet -d ": C:\Program Files\dotnet\sdk\2.1.400\Sdks\Microsoft.NET.Sdk\targets\GenerateDeps\GenerateDeps.proj