Fission: Cross-namespace Package read via unvalidated PackageRef in Function admission webhook

Fission is an open-source, Kubernetes-native serverless framework that simplifies the deployment of functions and applications on Kubernetes. Prior to version 1.24.0, a Fission Function spec carries three reference types — Secret, ConfigMap, and Package. The first two were namespace-validated by the admission webhook; PackageRef.Namespace was not. This issue has been patched in version 1.24.0.