Update flask-sqlalchemy to 2.4.4

[pyup-bot]

This PR updates Flask-SQLAlchemy from 2.4.3 to 2.4.4.

Changelog

2.4.4

-------------

Released 2020-07-14

-   Change base class of meta mixins to ``type``. This fixes an issue
 caused by a regression in CPython 3.8.4. :issue:`852`

Links

• PyPI: https://pypi.org/project/flask-sqlalchemy
• Changelog: https://pyup.io/changelogs/flask-sqlalchemy/
• Repo: https://github.com/pallets/flask-sqlalchemy
• Docs: https://pythonhosted.org/Flask-SQLAlchemy/

[coveralls]

Pull Request Test Coverage Report for Build 773

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 0.0%

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Totals
Change from base Build 759:	0.0%
Covered Lines:	0
Relevant Lines:	0

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💛 - Coveralls