fix(php): fix stub argument, string not str

Author: burgesQ

frankenphp.stub.php

@@ -32,4 +32,4 @@ function frankenphp_response_headers(): array|bool {}
  */
 function apache_response_headers(): array|bool {}
 
-function frankenphp_log_message(str $message, int $level): void {}
+function frankenphp_log_message(string $message, int $level): void {}