Set image working directory (#111)

set the working directory of the generated container

Author: baronfel

Microsoft.NET.Build.Containers/CreateNewImage.cs

@@ -109,6 +109,7 @@ public override bool Execute()
 
         Layer newLayer = Layer.FromDirectory(PublishDirectory, WorkingDirectory);
         image.AddLayer(newLayer);
+        image.WorkingDirectory = WorkingDirectory;
         image.SetEntrypoint(Entrypoint.Select(i => i.ItemSpec).ToArray(), EntrypointArgs.Select(i => i.ItemSpec).ToArray());
 
         if (OutputRegistry.StartsWith("docker://"))