--default-targets use CNAME instead of IP

[JohnyGemityg]

What would you like to be added:
Hi,

would it be possible to use default-targets as a target CNAME value instead of A record with IP?

Why is this needed:

in our enviroment we use a GEO balancing that manage DNS records based od GEO location and based on availability. We need to said this ingress example.web.app is CNAME to ingress-k8s.web.app because ingress-k8s.web.app is managed by Global traffic manager.

[remunda]

As I looked into the code, this change could solve it. But its not released yet. Right @cgroschupp? fd8c427

[cgroschupp]

@remunda Yes, you are right, it is not released. but you can use a staging image: https://console.cloud.google.com/gcr/images/k8s-staging-external-dns/GLOBAL/external-dns

See pr: #3745

[JohnyGemityg]

Using image based on master branch works as expected. Thank you, problem solved. Looking for a new official release.