fix: infra/roles/users_and_groups/requirements.txt to reduce vulnerab…

…ilities

The following vulnerabilities are fixed by pinning transitive dependencies:
- https://snyk.io/vuln/SNYK-PYTHON-URLLIB3-7267250
- https://snyk.io/vuln/SNYK-PYTHON-ZIPP-7430899

infra/roles/users_and_groups/requirements.txt

@@ -1,3 +1,5 @@
 docker==3.5.1
 molecule==2.19.0
-pytest==3.9.3
+pytest==3.9.3
+urllib3>=2.2.2 # not directly required, pinned by Snyk to avoid a vulnerability
+zipp>=3.19.1 # not directly required, pinned by Snyk to avoid a vulnerability