fix: doc-requirements.txt to reduce vulnerabilities (#479)

The following vulnerabilities are fixed by pinning transitive dependencies:
- https://snyk.io/vuln/SNYK-PYTHON-CERTIFI-3164749
- https://snyk.io/vuln/SNYK-PYTHON-CERTIFI-5805047
- https://snyk.io/vuln/SNYK-PYTHON-JINJA2-6150717
- https://snyk.io/vuln/SNYK-PYTHON-PYGMENTS-1086606
- https://snyk.io/vuln/SNYK-PYTHON-PYGMENTS-1088505
- https://snyk.io/vuln/SNYK-PYTHON-PYGMENTS-5750273
- https://snyk.io/vuln/SNYK-PYTHON-REQUESTS-5595532
- https://snyk.io/vuln/SNYK-PYTHON-SETUPTOOLS-3180412
- https://snyk.io/vuln/SNYK-PYTHON-SPHINX-570772
- https://snyk.io/vuln/SNYK-PYTHON-SPHINX-570773
- https://snyk.io/vuln/SNYK-PYTHON-SPHINX-5811865
- https://snyk.io/vuln/SNYK-PYTHON-SPHINX-5812109

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

Author: EngHabu

doc-requirements.txt

@@ -109,3 +109,4 @@ urllib3==2.1.0
     # via requests
 zipp==3.17.0
     # via importlib-metadata
+setuptools>=65.5.1 # not directly required, pinned by Snyk to avoid a vulnerability