Setting Log Handler Formatter

I'd like to have logs formatted using [ecs_logging](https://www.elastic.co/guide/en/ecs-logging/python/current/installation.html#logging) and noticed adding a handler to my app does nothing to change the log format in the CloudWatch LogGroup.

This for example has no impact to log format:
```
LOGGER = logging.getLogger(__package__)
LOGGER.setLevel(level=logging.INFO)
handler = logging.StreamHandler()
handler.setFormatter(ecs_logging.StdlibFormatter())
LOGGER.addHandler(handler)
```

I also tried brute forcing the formatter with no luck:
```
def set_formatter():
for logger in logging.root.manager.loggerDict.values():
if isinstance(logger, logging.PlaceHolder):
continue

if logger.hasHandlers():
for handler in logger.handlers:
handler.setFormatter(ecs_logging.StdlibFormatter())

@hook.handler(HookInvocationPoint.CREATE_PRE_PROVISION)
def pre_create_handler(
session: Optional[SessionProxy],
request: BaseHookHandlerRequest,
callback_context: MutableMapping[str, Any],
type_configuration: TypeConfigurationModel,
) -> ProgressEvent:
set_formatter()
LOGGER.info(jsonify_hook_context(request=request))
return ProgressEvent(status=OperationStatus.SUCCESS)
```

Is there a way to set the format for log output using this library?