Bump sqlalchemy from 2.0.20 to 2.0.21

Bumps [sqlalchemy](https://github.com/sqlalchemy/sqlalchemy) from 2.0.20 to 2.0.21.
- [Release notes](https://github.com/sqlalchemy/sqlalchemy/releases)
- [Changelog](https://github.com/sqlalchemy/sqlalchemy/blob/main/CHANGES.rst)
- [Commits](https://github.com/sqlalchemy/sqlalchemy/commits)

---
updated-dependencies:
- dependency-name: sqlalchemy
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>