Add batch flag for publish commands

cmd/publish_update.go

@@ -102,6 +102,7 @@ Example:
 	cmd.Flag.String("passphrase-file", "", "GPG passhprase-file for the key (warning: could be insecure)")
 	cmd.Flag.Bool("skip-signing", false, "don't sign Release files with GPG")
 	cmd.Flag.Bool("force-overwrite", false, "overwrite files in package pool in case of mismatch")
+	cmd.Flag.Bool("batch", false, "run gpg with a detached tty")
 
 	return cmd
 }