fix: requirements/requirements_dev.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/requirements_dev.txt

@@ -7,5 +7,5 @@ pytest-cov>=2.6.1
 coveralls>=1.6.0
 dbus-python
 -r ../requirements.txt
-urllib3>=2.2.2 # not directly required, pinned by Snyk to avoid a vulnerability
+urllib3>=2.6.3 # not directly required, pinned by Snyk to avoid a vulnerability
 zipp>=3.19.1 # not directly required, pinned by Snyk to avoid a vulnerability