SQLA2.1: compatibility with changes to ScalarAttributeImpl

[Dev-iL]

Hello,

I recently attempted to test the compatibility of Apache Airflow with the SQLAlchemy 2.1 beta. CI reported multiple issues related to sqlalchemy-utils attempting to import sqlalchemy.orm.attributes.ScalarAttributeImpl, e.g.

from sqlalchemy_utils import UUIDType
/usr/python/lib/python3.13/site-packages/sqlalchemy_utils/__init__.py:46: in <module>
    from .generic import generic_relationship  # noqa
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
/usr/python/lib/python3.13/site-packages/sqlalchemy_utils/generic.py:15: in <module>
    class GenericAttributeImpl(attributes.ScalarAttributeImpl):
                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
E   AttributeError: module 'sqlalchemy.orm.attributes' has no attribute 'ScalarAttributeImpl'

See more examples in the CI logs below:

• https://github.com/apache/airflow/actions/runs/21493207091/job/61923032136
• https://github.com/apache/airflow/actions/runs/21493207091/job/61923032069

I believe that the breaking change was this:

• sqlalchemy/sqlalchemy@f7e2b1a

[Dev-iL]

Closing as duplicate of #800