add dunder methods

Author: hoel-bagard

stubs/behave/behave/runner.pyi

@@ -19,6 +19,10 @@ class Context:
     active_outline: Any
 
     def __init__(self, runner: Any) -> None: ...
+    def __getattr__(self, name: str) -> Any: ...
+    def __setattr__(self, name: str, value: Any) -> None: ...
+    def __delattr__(self, name: str) -> None: ...
+    def __contains__(self, name: str) -> bool: ...
     def abort(self, reason: str | None = None) -> None: ...
     def use_or_assign_param(self, name: str, value: Any) -> Any: ...
     def use_or_create_param(self, name: str, factory_func: Callable[_P, Any], *args: _P.args, **kwargs: _P.kwargs) -> Any: ...