Fix PVC path

Summary

PVC mount path needs to be updated

Steps to reproduce

create file in postgres pod located at /var/lib/postgresql/data/pgdata
scale postgres pod to 0 then back to 1

What is the current behavior?

the file disappears

What is the expected behavior?

the file should remain

Possible fixes

update postgres mount path in values to include /data

persistence:
  resourcePolicy: keep
  size: 20Gi
  subPath: "pgdata"
  mountPath: /var/lib/postgresql/data