fix: requirements.txt to reduce vulnerabilities

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

Author: snyk-bot

requirements.txt

@@ -11,4 +11,5 @@ tqdm==4.62.3
 olefile==0.46
 Pillow==8.3.2
 py-bcrypt==0.4
-scikit_learn==0.22.2.post1
+scikit_learn==0.22.2.post1
+urllib3>=2.5.0 # not directly required, pinned by Snyk to avoid a vulnerability