Added missing using

Author: MichalPavlik

src/Containers/Microsoft.NET.Build.Containers/AuthHandshakeMessageHandler.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System.Collections.Concurrent;
+using System.ComponentModel;
 using System.Diagnostics;
 using System.Diagnostics.CodeAnalysis;
 using System.Net;