fix: requirements-dev.txt to reduce vulnerabilities

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

Author: snyk-bot

requirements-dev.txt

@@ -6,4 +6,5 @@ flake8==3.9.2
 dataclasses
 scanoss
 importlib-metadata==4.12.0
-pytest-xdist
+pytest-xdist
+zipp>=3.19.1 # not directly required, pinned by Snyk to avoid a vulnerability