apiVersion: kyverno.io/v1
kind: ClusterPolicy
metadata:
  name: mutate-ingress-host
spec:
  rules:
  - name: mutate-rules-host
    match:
      any:
      - resources:
          kinds:
          - Ingress
    mutate:
      patchesJson6902: |-
        - op: replace
          path: /spec/rules/0/host
          value: "{{request.object.spec.rules[0].host}}.mycompany.com"