fix: api/requirements.txt to reduce vulnerabilities

The following vulnerabilities are fixed by pinning transitive dependencies:
- https://snyk.io/vuln/SNYK-PYTHON-WERKZEUG-14908843

Author: snyk-bot

api/requirements.txt

@@ -41,6 +41,6 @@ six==1.14.0
 toml==0.10.0
 typed-ast==1.4.1
 wcwidth==0.1.9
-Werkzeug==1.0.1
+Werkzeug==3.1.5
 WTForms==2.3.1
 zipp==3.1.0