fix: requirements.txt to reduce vulnerabilities (#69)

The following vulnerabilities are fixed by pinning transitive dependencies:
- https://snyk.io/vuln/SNYK-PYTHON-WERKZEUG-6808933

Co-authored-by: snyk-bot <snyk-bot@snyk.io>

requirements.txt

@@ -2,4 +2,4 @@
 flask==3.0.3
 flask_wtf==1.2.1
 prometheus-flask-exporter==0.23.0
-werkzeug>=3.0.1 # not directly required, pinned by Snyk to avoid a vulnerability
+werkzeug>=3.0.3 # not directly required, pinned by Snyk to avoid a vulnerability