

**Description**

We are using a 3rd party executor which has the ability to use multiple queues, however the `default_queue` is defined under the `celery` heading and is used regardless of the executor that you are using.

See: https://github.com/apache/airflow/blob/2.0.1/airflow/models/baseoperator.py#L366

It would be nice to decouple the default_queue configuration argument away from the celery section to allow other executors to utilise this functionality with less confusion.

**Are you willing to submit a PR?**

Yep! Will open a pull request shortly


**Related Issues**

Not that I'm aware of.

airflow/configuration.py
if section == deprecated_section:
            warnings.warn(
                'The {old} option in [{section}] has been renamed to {new} - the old '
                'setting has been used, but please update your config.'.format(
                    old=deprecated_name,
                    new=key,
                    section=section,
                ),
                DeprecationWarning,
                stacklevel=3,
            )
        else:
            warnings.warn(
                'The {old_key} option in [{old_section}] has been moved to the {new_key} option in '
                '[{new_section}] - the old setting has been used, but please update your config.'.format(
                    old_section=deprecated_section,
                    old_key=deprecated_name,
                    new_key=key,
                    new_section=section,
                ),
                DeprecationWarning,
                stacklevel=3,
            )
    def __getstate__(self):