Update stubs

Author: phpstan-bot

stubs/ext/ftp/ftp_nb_get.php

@@ -6,6 +6,6 @@ function ftp_nb_get($ftp, string $local_filename, string $remote_filename, int $
 {
 }
 #[\Since('8.1')]
-function ftp_nb_get(\FTP\Connection $ftp, string $local_filename, string $remote_filename, int $mode = FTP_BINARY, int $offset = 0) : int
+function ftp_nb_get(\FTP\Connection $ftp, string $local_filename, string $remote_filename, int $mode = FTP_BINARY, int $offset = 0) : int|false
 {
 }