chore(deps): bump flask-cors from 3.0.8 to 3.0.9

Bumps [flask-cors](https://github.com/corydolphin/flask-cors) from 3.0.8 to 3.0.9.
- [Release notes](https://github.com/corydolphin/flask-cors/releases)
- [Changelog](https://github.com/corydolphin/flask-cors/blob/master/CHANGELOG.md)
- [Commits](corydolphin/flask-cors@3.0.8...3.0.9)

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

requirements/common.txt

@@ -37,7 +37,7 @@ python-magic==0.4.18
 python-dotenv==0.14.0
 python-geoip==1.2
 marrow.mailer==4.0.3
-flask-cors==3.0.8
+flask-cors==3.0.9
 python-pentabarf-xml==0.20
 python-geoip-geolite2==2015.303
 pycountry==20.7.3