Update flask requirement from ~=1.1.2 to ~=2.0.1

Updates the requirements on [flask](https://github.com/pallets/flask) to permit the latest version.
- [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]

requirements.txt

@@ -2,7 +2,7 @@ Flask-Gzip~=0.2
 Flask-Mail~=0.9.1
 Flask-Migrate~=2.7.0
 Flask-pyoidc~=3.7.0
-Flask~=1.1.2
+Flask~=2.0.1
 csh_ldap~=2.3.1
 ddtrace
 flask_sqlalchemy~=2.5.1