fix: example/requirements.txt to reduce vulnerabilities

The following vulnerabilities are fixed by pinning transitive dependencies:
- https://snyk.io/vuln/SNYK-PYTHON-SETUPTOOLS-7448482

Author: snyk-bot

example/requirements.txt

@@ -2,7 +2,7 @@ pyop
 Flask
 gunicorn
 oic>=1.2.1
-setuptools>=65.5.1 # not directly required, pinned by Snyk to avoid a vulnerability
+setuptools>=70.0.0 # not directly required, pinned by Snyk to avoid a vulnerability
 werkzeug>=3.0.1 # not directly required, pinned by Snyk to avoid a vulnerability
 requests>=2.32.2 # not directly required, pinned by Snyk to avoid a vulnerability
 urllib3>=2.2.2 # not directly required, pinned by Snyk to avoid a vulnerability