[Ignore] no need for package sources (PowerShell#803)

Author: TylerLeonhardt

NuGet.Config

@@ -3,10 +3,4 @@
   <solution>
     <add key="disableSourceControlIntegration" value="true" />
   </solution>
-  <packageSources>
-    <clear />
-    <add key="CI Builds (dotnet-core)" value="https://www.myget.org/F/dotnet-core/api/v3/index.json" />
-    <add key="nuget.org" value="https://api.nuget.org/v3/index.json" />
-    <add key="powershell-core" value="https://powershell.myget.org/F/powershell-core/api/v3/index.json" />
-  </packageSources>
-</configuration>
+</configuration>