Fix/sqlalchemy 2.0 compatibility - chapter6 UoW by rickywesker · Pull Request #110 · cosmicpython/code

- Replace deprecated mapper() with registry.map_imperatively()
- Replace session.query() with session.scalars(select())
- Wrap raw SQL strings with text()
- Replace clear_mappers() with mapper_registry.dispose()
- Update requirements.txt to require sqlalchemy>=2.0