maybe fix stubtest (#5746)

Co-authored-by: Jelle Zijlstra <[email protected]>

Author: Akuli

stubs/Pillow/PIL/Image.pyi

@@ -120,7 +120,7 @@ class Image:
     def __exit__(self, *args: Any) -> None: ...
     def close(self) -> None: ...
     def __eq__(self, other: object) -> bool: ...
-    def __array__(self) -> Any: ...  # returns numpy.array()
+    def __array__(self, dtype=...) -> Any: ...  # returns numpy.array()
     def __getstate__(self) -> _ImageState: ...
     def __setstate__(self, state: _ImageState) -> None: ...
     def tobytes(self, encoder_name: str = ..., *args) -> bytes: ...