Bump flask-migrate from 2.6.0 to 2.7.0 (#441)

Bumps [flask-migrate](https://github.com/miguelgrinberg/flask-migrate) from 2.6.0 to 2.7.0.
- [Release notes](https://github.com/miguelgrinberg/flask-migrate/releases)
- [Changelog](https://github.com/miguelgrinberg/Flask-Migrate/blob/master/CHANGES.md)
- [Commits](miguelgrinberg/Flask-Migrate@v2.6.0...v2.7.0)

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Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>
Co-authored-by: Aaron Suarez <aaron-suarez@users.noreply.github.com>

Author: dependabot-preview[bot]

poetry.lock

@@ -14,7 +14,7 @@ click = "7.1.2"
 flake8 = "3.8.4"
 flask = "1.1.2"
 Flask-Cors = "3.0.10"
-Flask-Migrate = "2.6.0"
+Flask-Migrate = "2.7.0"
 prometheus_client = "0.9.0"
 psycopg2-binary = "2.8.6"
 py-healthcheck = "1.10.1"