title: DbProviderFactories.GetFactoryClasses returns no results after installing .NET SQL Client in .NET Core 2.1
body: <p>I'm porting a library over to .NET Core 2.1 now that it has support for DbProviderFactory. For the most part it has gone fine - it compiles, but when run I get an error:</p>
  
  <blockquote>
    <p>System.ArgumentException: 'The specified invariant name 'System.Data.SqlClient' wasn't found in the list of registered .NET Data Providers.'</p>
  </blockquote>
  
  <p>I've used <code>DbProviderFactories.GetFactoryClasses()</code> to check if there are any providers installed, and there doesn't appear to be (0 rows in the resulting table).</p>
  
  <p>So I guess my question is, how can I install the data providers for .NET Core? I've got .NET Framework 4.5 on the machine and it is picking up the data providers without any issue. I don't want to install <code>System.Data.SqlClient</code> as a Nuget for the local project, since that would add a dependency that would make the <code>DbProviderFactory</code> irrelevent. That said, I have attempted to install <code>System.Data.SqlClient</code> in a project that uses my library as a test, and it still isn't picked up.</p>