Use spf13/cobra for docker tag

This fix is part of the effort to convert commands to spf13/cobra #23211.

Thif fix coverted command `docker tag` to use spf13/cobra

Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

cobraadaptor/adaptor.go

@@ -54,6 +54,7 @@ func NewCobraAdaptor(clientFlags *cliflags.ClientFlags) CobraAdaptor {
 		image.NewRemoveCommand(dockerCli),
 		image.NewSearchCommand(dockerCli),
 		image.NewImportCommand(dockerCli),
+		image.NewTagCommand(dockerCli),
 		network.NewNetworkCommand(dockerCli),
 		volume.NewVolumeCommand(dockerCli),
 	)

usage.go

@@ -25,7 +25,6 @@ var DockerCommandUsage = []Command{
 	{"rm", "Remove one or more containers"},
 	{"save", "Save one or more images to a tar archive"},
 	{"stats", "Display a live stream of container(s) resource usage statistics"},
-	{"tag", "Tag an image into a repository"},
 	{"update", "Update configuration of one or more containers"},
 	{"version", "Show the Docker version information"},
 }