Add missing parameter on bulk_save_objects

[vineus]

From SQLAlchemy 1.3

from documentation: https://docs.sqlalchemy.org/en/14/orm/session_api.html#sqlalchemy.orm.Session.bulk_save_objects

method sqlalchemy.orm.Session.bulk_save_objects(objects, return_defaults=False, update_changed_only=True, preserve_order=True)

preserve_order –

when True, the order of inserts and updates matches exactly the order in which the objects are given. When False, common types of objects are grouped into inserts and updates, to allow for more batching opportunities.

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