Update dependency flask to v3.1.1

Author: renovate[bot]

requirements.txt

@@ -6,7 +6,7 @@ cssmin==0.2.0 ; python_version >= "3.10" and python_version < "4.0"
 faker==21.0.0 ; python_version >= "3.10" and python_version < "4.0"
 flake8==6.1.0 ; python_version >= "3.10" and python_version < "4.0"
 flask-assets==2.1.0 ; python_version >= "3.10" and python_version < "4.0"
-flask==3.0.0 ; python_version >= "3.10" and python_version < "4.0"
+flask==3.1.1 ; python_version >= "3.10" and python_version < "4.0"
 gunicorn==21.2.0 ; python_version >= "3.10" and python_version < "4.0"
 isort==5.13.2 ; python_version >= "3.10" and python_version < "4.0"
 itsdangerous==2.1.2 ; python_version >= "3.10" and python_version < "4.0"