helm-external-secrets/config/certmanager/kustomizeconfig.yaml

# This configuration is for teaching kustomize how to update name ref and var substitution 
nameReference:
- kind: Issuer
  group: cert-manager.io
  fieldSpecs:
  - kind: Certificate
    group: cert-manager.io
    path: spec/issuerRef/name

varReference:
- kind: Certificate
  group: cert-manager.io
  path: spec/commonName
- kind: Certificate
  group: cert-manager.io
  path: spec/dnsNames