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

@@ -46,7 +46,7 @@ six==1.16.0
     #   xml2rfc
 sortedcontainers==2.4.0
     # via intervaltree
-urllib3==1.26.18
+urllib3==2.5.0
     # via requests
 webencodings==0.5.1
     # via html5lib