message: Fix a deprecation warning in bootstrap.php
  (Deprecate passing null to non-nullable arguments of internal functions)
diff: @@ -252,7 +252,7 @@ class SwooleLibraryBuilder
  if ($this->checkFileChange) {
  preg_match(
  '/^(\d+)/',
  - trim(shell_exec('cd ' . $this->libraryDir . ' && git diff --shortstat')),
  + trim(shell_exec('cd ' . $this->libraryDir . ' && git diff --shortstat') ?? ''),
  $file_change
  );
  $file_change = (int)($file_change[1] ?? 0);
  