title: Unable to find ConfigurationErrorsException nuget package or assembly .net Core 2.2
body: <p>I am trying to use <strong>ConfigurationErrorsException</strong> in a .net Core 2.2 application.
  I checked the documentation here: <a href="https://docs.microsoft.com/en-us/dotnet/api/system.configuration.configurationerrorsexception?view=netcore-2.2" rel="nofollow noreferrer">https://docs.microsoft.com/en-us/dotnet/api/system.configuration.configurationerrorsexception?view=netcore-2.2</a>, but I cannot figure out which NuGet package I need to install in order to be able to use this class, if any.
  Even using the fully qualified name (<em>System.Configuration.ConfigurationErrorsException</em>) I cannot resolve the type.</p>