build(deps): bump flask-cors from 3.0.8 to 3.0.9 in /backend

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[bot] <[email protected]>

Author: dependabot[bot]

backend/requirements.txt

@@ -3,7 +3,7 @@ connexion==2.7.0
 datadog==0.38.0
 fakeredis==1.4.3
 Flask==1.1.2
-Flask-Cors==3.0.8
+Flask-Cors==3.0.9
 flask-talisman==0.7.0
 google-cloud-storage==1.30.0
 gunicorn==20.0.4