Bump flask-sqlalchemy in /{{cookiecutter.app_name}}/requirements

Bumps [flask-sqlalchemy](https://github.com/pallets/flask-sqlalchemy) from 2.4.0 to 2.4.1.
- [Release notes](https://github.com/pallets/flask-sqlalchemy/releases)
- [Changelog](https://github.com/pallets/flask-sqlalchemy/blob/master/CHANGES.rst)
- [Commits](https://github.com/pallets/flask-sqlalchemy/compare/2.4.0...2.4.1

)

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