backport some fixes from main

cmd/root.go

@@ -71,6 +71,7 @@ var (
 )
 
 func init() {
+	rootCmd.CompletionOptions.DisableDefaultCmd = true
 	rootCmd.Flags().BoolP("version", "v", false, "")
 	rootCmd.Version = version.GetAsString()
 	rootCmd.SetVersionTemplate(`{{printf "SFTPGo "}}{{printf "%s" .Version}}