Upsert Dag/Task History

[fritz-astronomer]

Was previously excluded to make things simpler - we may be able to attempt to upsert, and fall back to insert if we can't. This may be a hassle, depending on what sqlalchemy versions the syntax is/isn't available with 🤔 but this might work

try:
    from sqlalchemy.dialects.postgresql import insert
    self.session.execute(
        insert(table).values(items).on_conflict_do_nothing()
    )
except ImportError:
    self.session.execute(
        table.insert().values(items)
    )