fix: examples/http/server/requirements.txt to reduce vulnerabilities

The following vulnerabilities are fixed by pinning transitive dependencies:
- https://snyk.io/vuln/SNYK-PYTHON-WERKZEUG-6041510

Author: snyk-bot

examples/http/server/requirements.txt

@@ -1,3 +1,4 @@
 ../../..
 flask
 mysql-connector-python==8.0.23
+werkzeug>=3.0.1 # not directly required, pinned by Snyk to avoid a vulnerability