Added the durable parameter in Atomic decorator and context-manager (#…

…172)

Hello,

Just stumbled across a missing parameter inside the `Atomic` context-manager which was added in `Django 3.2`.

Hope this helps...

django-stubs/db/transaction.pyi

@@ -28,7 +28,7 @@ _C = TypeVar("_C", bound=Callable[..., Any])
 class Atomic:
     using: Optional[str] = ...
     savepoint: bool = ...
-    def __init__(self, using: Optional[str], savepoint: bool) -> None: ...
+    def __init__(self, using: Optional[str], savepoint: bool, durable: bool = ...) -> None: ...
     # When decorating, return the decorated function as-is, rather than clobbering it as ContextDecorator does.
     def __call__(self, func: _C) -> _C: ...
     def __enter__(self) -> None: ...
@@ -40,7 +40,7 @@ def atomic(using: _C) -> _C: ...
 
 # Decorator or context-manager with parameters
 @overload
-def atomic(using: Optional[str] = ..., savepoint: bool = ...) -> Atomic: ...
+def atomic(using: Optional[str] = ..., savepoint: bool = ..., durable: bool = ...) -> Atomic: ...
 
 # Bare decorator
 @overload