Bump flask-sqlalchemy from 2.4.2 to 2.4.3

Bumps [flask-sqlalchemy](https://github.com/pallets/flask-sqlalchemy) from 2.4.2 to 2.4.3.
- [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/2.4.2...2.4.3)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

setup.py

@@ -33,7 +33,7 @@ setup(
     packages=find_packages(exclude=['tests', 'tests.*']),
     install_requires=[
         'Flask==1.1.2',
-        'Flask-SQLAlchemy==2.4.2',
+        'Flask-SQLAlchemy==2.4.3',
         'Flask-Migrate==2.5.3',
         'Flask-Bootstrap==3.3.7.1',
         'Flask-WTF==0.14.3',