Upgrade
Before updating the charm you need to back up the database using the PostgreSQL charm’s create-backup action.
juju run postgresql-k8s/leader create-backup
Additional information can be found about backing up in the PostgreSQL charm’s documentation.
Then you can upgrade the Hockeypuck charm:
juju refresh hockeypuck-k8s
After upgrading the Hockeypuck charm you need to rebuild the prefix tree:
juju run hockeypuck-k8s/0 rebuild-prefix-tree