fix: pip-sample/requirements.txt to reduce vulnerabilities

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

pip-sample/requirements.txt

@@ -64,3 +64,4 @@ webencodings==0.5.1
 Werkzeug==0.14.1
 widgetsnbextension==3.4.2
 xlrd==1.1.0
+setuptools>=70.0.0 # not directly required, pinned by Snyk to avoid a vulnerability