Merge pull request #20845 from Microsoft/jstarks/default_to_npipe

Windows: Default to npipe transport

opts/hosts_windows.go

@@ -3,4 +3,4 @@
 package opts
 
 // DefaultHost constant defines the default host string used by docker on Windows
-var DefaultHost = DefaultTCPHost
+var DefaultHost = "npipe://" + DefaultNamedPipe