Zone - Filter all the zones based on a tag

The following example policy will filter all the zones in the tenancy based on a specified tag

policies:
- name: filter-zones
  description: |
    Filter all the zones in the tenancy based on a tag
  resource: oci.zone
  filters:
   - type: value
     key: 'freeform_tags.cloud_custodian'
     value: 'true'
     op: eq