Use str for key_prefix

Author: Viicos

django-stubs/views/decorators/cache.pyi

@@ -4,7 +4,7 @@ from typing import Any
 from . import _ViewFuncT
 
 def cache_page(
-    timeout: float | None, *, cache: Any | None = ..., key_prefix: Any | None = ...
+    timeout: float | None, *, cache: Any | None = ..., key_prefix: str | None = ...
 ) -> Callable[[_ViewFuncT], _ViewFuncT]: ...
 def cache_control(**kwargs: Any) -> Callable[[_ViewFuncT], _ViewFuncT]: ...
 def never_cache(view_func: _ViewFuncT, /) -> _ViewFuncT: ...