fix: requirements.txt to reduce vulnerabilities

The following vulnerabilities are fixed by pinning transitive dependencies:
- https://snyk.io/vuln/SNYK-PYTHON-PROTOBUF-10364902
- https://snyk.io/vuln/SNYK-PYTHON-URLLIB3-10390193
- https://snyk.io/vuln/SNYK-PYTHON-URLLIB3-10390194

Author: snyk-bot

requirements.txt

@@ -31,3 +31,5 @@ fonttools>=4.43.0 # not directly required, pinned by Snyk to avoid a vulnerabili
 holidays>=0.45 # not directly required, pinned by Snyk to avoid a vulnerability
 zipp>=3.19.1 # not directly required, pinned by Snyk to avoid a vulnerability
 nltk>=3.8.2 # not directly required, pinned by Snyk to avoid a vulnerability
+protobuf>=4.25.8 # not directly required, pinned by Snyk to avoid a vulnerability
+urllib3>=2.5.0 # not directly required, pinned by Snyk to avoid a vulnerability