chore(deps): update dependency flask to v3.1.2 (#142)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

src/backend/requirements.txt

@@ -1,4 +1,4 @@
-Flask==3.1.1
+Flask==3.1.2
 Flask-SocketIO==5.5.1
 Flask-SQLAlchemy==3.1.1
 Flask-Login==0.6.3