Add overload to cast for objects (#4851)

Fixes #4810

Author: septatrix

stdlib/2/typing.pyi

@@ -460,6 +460,8 @@ def get_type_hints(
 def cast(tp: Type[_T], obj: Any) -> _T: ...
 @overload
 def cast(tp: str, obj: Any) -> Any: ...
+@overload
+def cast(tp: object, obj: Any) -> Any: ...
 
 # Type constructors
 

stdlib/3/typing.pyi

@@ -633,6 +633,8 @@ if sys.version_info >= (3, 8):
 def cast(typ: Type[_T], val: Any) -> _T: ...
 @overload
 def cast(typ: str, val: Any) -> Any: ...
+@overload
+def cast(typ: object, val: Any) -> Any: ...
 
 # Type constructors