fix @classproperty return type (#58)

Author: mkurnikov

django-stubs/utils/decorators.pyi

@@ -1,21 +1,19 @@
 from typing import Any, Callable, Optional, Set, Tuple, Type, Union
 
-from django.middleware.cache import CacheMiddleware
-from django.test.testcases import LiveServerTestCase
 from django.utils.deprecation import MiddlewareMixin
 
 class classonlymethod(classmethod): ...
 
 def method_decorator(
     decorator: Union[Callable, Set[Callable], Tuple[Callable, Callable]], name: str = ...
 ) -> Callable: ...
-def decorator_from_middleware_with_args(middleware_class: Type[CacheMiddleware]) -> Callable: ...
+def decorator_from_middleware_with_args(middleware_class: Type[MiddlewareMixin]) -> Callable: ...
 def decorator_from_middleware(middleware_class: Type[MiddlewareMixin]) -> Callable: ...
 def available_attrs(fn: Any): ...
 def make_middleware_decorator(middleware_class: Type[MiddlewareMixin]) -> Callable: ...
 
 class classproperty:
     fget: Optional[Callable] = ...
     def __init__(self, method: Optional[Callable] = ...) -> None: ...
-    def __get__(self, instance: Optional[LiveServerTestCase], cls: Type[LiveServerTestCase] = ...) -> str: ...
+    def __get__(self, instance: Any, cls: Optional[type] = ...) -> Any: ...
     def getter(self, method: Callable) -> classproperty: ...