yet another fix the _pygit2.pyi

Author: DinhHuy2010

pygit2/_pygit2.pyi

@@ -1,5 +1,5 @@
 from io import IOBase
-from typing import Any, Iterator, Literal, Optional, TypeAlias, overload
+from typing import Any, Callable, Iterator, Literal, Optional, TypeAlias, overload
 
 from . import Index
 from .enums import (
@@ -822,3 +822,5 @@ def init_file_backend(path: str, flags: int = 0) -> object: ...
 def option(opt: Option, *args: Any) -> None: ...
 def reference_is_valid_name(refname: str) -> bool: ...
 def tree_entry_cmp(a: Object, b: Object) -> int: ...
+
+_cache_enums: Callable[..., None]