update help output

applications/venv-manager/main.go

@@ -33,7 +33,7 @@ func main() {
 		fmt.Println("--controller string\n\t Controller URL and Port. (Default: 'localhost:55055')")
 		fmt.Println("--topology string\n\t Filename of the resulting topology file. (Default: 'venv.clab.yaml')")
 		fmt.Println("--sdnconfig string\n\t Filename of the resulting SDN configuration file. (Default: 'sdn_config.json')")
-		fmt.Println("--registry string\n\t URL of the container registry to use. Keep in mind that cEOS images and prebuild linux images with the gnmi target are not available on dockerhub. (Default: dockerhub)")
+		fmt.Println("--registry string\n\t URL of the container registry to use. Keep in mind that cEOS images and prebuild linux images with the gnmi target are not available on dockerhub. (Default: none (dockerhub))")
 		fmt.Println("--help\n\t Shows this help screen.")
 	}
 	flag.Parse()