community/py3-alembic, testing/py3-flask-migrate: upgrade
https://alembic.sqlalchemy.org/en/latest/changelog.html#change-1.10.3
https://github.com/miguelgrinberg/Flask-Migrate/blob/v4.0.4/CHANGES.md
both of them needed an upgrade to work properly:
- flask-migrate's tests don't work anymore due to some compatibility differences with newer alembic
- but upgrading that to 4.0.4 needs even newer alembic
Edited by Patrycja Rosa