build(deps): bump flask from 1.1.2 to 2.0.1 in /backend

Bumps [flask](https://github.com/pallets/flask) from 1.1.2 to 2.0.1.
- [Release notes](https://github.com/pallets/flask/releases)
- [Changelog](https://github.com/pallets/flask/blob/main/CHANGES.rst)
- [Commits](pallets/flask@1.1.2...2.0.1)

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

Author: dependabot[bot]

backend/requirements.txt

@@ -2,7 +2,7 @@
 connexion==2.9.0
 datadog==0.42.0
 fakeredis==1.6.0
-Flask==1.1.2
+Flask==2.0.1
 Flask-Cors==3.0.10
 flask-talisman==0.8.1
 google-cloud-storage==1.42.0