Bump flask from 3.1.2 to 3.1.3 in /backend (#739)

dependabot[bot] · web-flow · commit ac02bc0b8ffa · 2026-03-16T16:21:35.000+01:00
diff --git a/backend/requirements.txt b/backend/requirements.txt
@@ -1,4 +1,4 @@
-Flask==3.1.2
+Flask==3.1.3
 gunicorn==25.1.0
 flask-cors==6.0.2
 gpxpy==1.6.2
