[docker-py] Add str type to named parameter in Image.save() method (#15068)

Author: roberfi

stubs/docker/docker/models/images.pyi

@@ -26,7 +26,7 @@ class Image(Model):
     def tags(self) -> list[str]: ...
     def history(self) -> list[Any]: ...
     def remove(self, force: bool = False, noprune: bool = False) -> dict[str, Any]: ...
-    def save(self, chunk_size: int = 2097152, named: bool = False) -> Iterator[Any]: ...
+    def save(self, chunk_size: int = 2097152, named: str | bool = False) -> Iterator[Any]: ...
     def tag(self, repository: str, tag: str | None = None, **kwargs) -> bool: ...
 
 class RegistryData(Model):