fix: requirements.txt to reduce vulnerabilities

The following vulnerabilities are fixed by pinning transitive dependencies:
- https://snyk.io/vuln/SNYK-PYTHON-URLLIB3-14896210

Author: snyk-bot

requirements.txt

@@ -15,5 +15,5 @@ PyNaCl==1.3.0
 requests==2.23.0
 SecretStorage==3.1.2
 six==1.14.0
-urllib3==1.25.9
+urllib3==2.6.3
 zipp==3.1.0