Can't rotate expired admission controller certificate

Had an issue whereby the self-signed admission controller certificate on the mutating/validating webhook had expired and couldn't be rotated...because it was expired.

After a few different approaches, Alex Emery tested and recommended:
kubectl delete validatingwebhookconfigurations.admissionregistration.k8s.io couchbase-couchbase-admission-controller
kubectl delete mutatingwebhookconfigurations.admissionregistration.k8s.io couchbase-couchbase-admission-controller
kubectl delete secrets couchbase-couchbase-admission-controller
helm upgrade couchbase couchbase/couchbase-operator
Which worked smoothly.

We should:

a) document this as a workaround (for both Helm and non-Helm deployments)

b) auto-renew the internal certificate on the webhook

c) increase the helm cert from 1 year to 10 like cao does