Allow copying ClusterIP value to ingress address

### Welcome! - [x] Yes, I've searched similar issues on [GitHub](https://github.com/traefik/traefik/issues) and didn't find any. - [x] Yes, I've searched similar issues on the [Traefik community forum](https://community.traefik.io) and didn't find any. ### What do you want to achieve with this Chart ? In IPv6 only clusters, the service IP for traefik using cluster-IP can lack the external-IP, because the cluster-IP is already world reachable, as seen in the following example: ``` [10:16] blind:~% kubectl -n ingress-traefik get svc NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE ingress-traefik ClusterIP 2a0a:e5c0:10:3::8:760e <none> 80/TCP,443/TCP 15d [10:16] blind:~% ``` When an ingress with this configuration is created, the ingress lacks the address field and while it *does work*, it is considered to be unfinished by operators suchs as argocd. The deployed ingress looks as follows: ``` kubectl -n ungleich-canary describe ingress canary-ingress-v2-traefik Name: canary-ingress-v2-traefik Labels: <none> Namespace: ungleich-canary Address: Ingress Class: traefik Default backend: <default> TLS: canary-ingress-v2-traefik-tls terminates canary.k8s-v2.place10.ungleich.ch Rules: Host Path Backends ---- ---- -------- canary.k8s-v2.place10.ungleich.ch / canary-ingress-v2-traefik:http ([2a0a:e5c0:10:2:f795:c91f:8ffc:bfa4]:5678) Annotations: argocd.argoproj.io/tracking-id: canary-ingress-v2-traefik:networking.k8s.io/Ingress:ungleich-canary/canary-ingress-v2-traefik Events: <none> ``` When deploying the same style of ingress/operator using ingress-nginx, the address field is filled out: ``` kubectl -n ingress-nginx get svc ingress-nginx-controller NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE ingress-nginx-controller ClusterIP 2a0a:e5c0:10:3::6eeb <none> 80/TCP,443/TCP 3y338d kubectl -n ungleich describe ingress ungleich-package-mirror Name: ungleich-package-mirror Labels: <none> Namespace: ungleich Address: 2a0a:e5c0:10:3::6eeb Ingress Class: nginx Default backend: <default> TLS: ungleich-package-mirror-tls terminates mirror.k8s.ungleich.ch,mirror.ungleich.ch,mirror.datacenterlight.ch Rules: Host Path Backends ---- ---- -------- deb.devuan.org / ungleich-package-mirror:80 ([2a0a:e5c0:10:2:2edc:cf99:c2db:e543]:80) mirror.k8s.ungleich.ch / ungleich-package-mirror:80 ([2a0a:e5c0:10:2:2edc:cf99:c2db:e543]:80) mirror.ungleich.ch / ungleich-package-mirror:80 ([2a0a:e5c0:10:2:2edc:cf99:c2db:e543]:80) mirror.datacenterlight.ch / ungleich-package-mirror:80 ([2a0a:e5c0:10:2:2edc:cf99:c2db:e543]:80) Annotations: argocd.argoproj.io/tracking-id: ungleich-package-mirror:networking.k8s.io/Ingress:ungleich/ungleich-package-mirror cert-manager.io/cluster-issuer: letsencrypt-prod nginx.ingress.kubernetes.io/ssl-redirect: false Events: <none> ``` I'd appreciate if traefik either: * supports doing this by default like nginx * or provides an option to take the clusterIP