fix: retain to delete

[roundspring2003]

Change PersistentVolume Reclaim Policy from Retain to Delete
Problem
When using persistentVolumeReclaimPolicy: Retain, after the PVC is deleted (e.g., during helm uninstall), the PV remains in a Released state and retains a reference (claimRef) to the old PVC. This prevents the PV from being automatically bound to a new PVC on subsequent deployments.

As a result, every time before redeploying, we had to manually run:

kubectl patch pv free5gc-pv-cert --type json -p '[{"op": "remove", "path": "/spec/claimRef"}]'

Solution
Change the reclaim policy to Delete. With this policy:

When the PVC is deleted, the PV will be automatically deleted as well
On the next deployment, a fresh PV will be created and bound to the new PVC
No manual intervention required between deployments
Note
This change is suitable for development and testing environments where data persistence across deployments is not required. For production environments where certificate data must be preserved, Retain policy should be used with proper operational procedures.

[Alonza0314]

@qawl987 Please help to check it！