Change Redis brokerUrl

[jeff-cook]

We have installed airflow with helm 1.18.0 using the redis default config. We are looking at switching to an external redis instance so we can get metrics.

However I see this comment that it can't be changed.

data:
  # Note: brokerUrl can only be set during install, not upgrade
  brokerUrl: ~

Is there a process to update the brokerUrl? Example does the database and all the PVCs need to be deleted?