Bump flask-migrate from 2.3.0 to 2.3.1
Bump flask-migrate from 2.3.0 to 2.3.1

Bumps [flask-migrate](https://github.com/miguelgrinberg/flask-migrate) from 2.3.0 to 2.3.1.
- [Release notes](https://github.com/miguelgrinberg/flask-migrate/releases)
- [Changelog](https://github.com/miguelgrinberg/Flask-Migrate/blob/master/CHANGELOG.md)
- [Commits](https://github.com/miguelgrinberg/flask-migrate/compare/v2.3.0...v2.3.1)

Signed-off-by: dependabot[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
jazzband/website,jazzband/website,jazzband/jazzband-site,jazzband/site,jazzband/site,jazzband/website,jazzband/jazzband-site,jazzband/website