fix: requirements.txt to reduce vulnerabilities

The following vulnerabilities are fixed by pinning transitive dependencies:
- https://snyk.io/vuln/SNYK-PYTHON-URLLIB3-14192442
- https://snyk.io/vuln/SNYK-PYTHON-URLLIB3-14192443

Author: snyk-bot

requirements.txt

@@ -122,7 +122,7 @@ six==1.16.0
     #   rfc3339-validator
 uri-template==1.1.0
     # via jsonschema
-urllib3==1.26.7
+urllib3==2.6.0
     # via requests
 watchdog==2.1.6
     # via mkdocs