fix: requirements.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.txt

@@ -16,3 +16,4 @@ igwn-auth-utils>=0.2.1
 flask
 tinydb
 pillow>=10.2.0
+zipp>=3.19.1 # not directly required, pinned by Snyk to avoid a vulnerability