Garbage collecting a CRD causes spurious "not found" error

[Angus Lees]

I decided to remove my Argo install, and hit this:

...
INFO  Garbage collecting clusterroles argo-ui-cluster-role (rbac.authorization.k8s.io/v1beta1)
INFO  Garbage collecting customresourcedefinitions workflows.argoproj.io (apiextensions.k8s.io/v1beta1)
ERROR the server could not find the requested resource (get workflows.argoproj.io)

(The CRD was deleted, and then gc tried to fetch instances of that custom resource)

kubecfg should ignore all variants of "not found" when walking the resources for garbage collection.