This commit removes support for the following API versions:
* `discovery.k8s.io/v1beta1` API version of EndpointSlice (no longer
served as of v1.25).
* `networking.k8s.io/v1beta1` API version of Ingress (no longer served
as of v1.22).
Closes#12884
Signed-off-by: Simon Pasquier <spasquie@redhat.com>