Clean up airgap image list

scripts/airgap/image-list.txt

@@ -1,7 +1,8 @@
 docker.io/coredns/coredns:1.6.3
+docker.io/k3sio/k8s-defaultbackend:1.5
+docker.io/k3sio/nginx-ingress-controller:0.30.0
 docker.io/rancher/klipper-helm:v0.2.3
 docker.io/rancher/klipper-lb:v0.1.2
 docker.io/rancher/local-path-provisioner:v0.0.11
 docker.io/rancher/metrics-server:v0.3.6
 docker.io/rancher/pause:3.1
-docker.io/k3sio/nginx-ingress-controller:0.30.0