Fix docs for raw deployment

[rachitchauhan43]

Expected Behavior

Docs say to install IngressClass:

apiVersion: networking.k8s.io/v1beta1
kind: IngressClass
metadata:
  name: istio
spec:
  controller: istio.io/ingress-controller

It errors out as apiVersion: networking.k8s.io/v1beta1 is no longer supported by istio version mentioned in quick_hack script.

Actual Behavior

Update apiVersion networking.k8s.io/v1

Steps to Reproduce the Problem

Try running quick_install.sh script with -r flag

Additional Info

Additional context
Add any other context about the problem here.

Install information:

• Platform (GKE, IKS, AKS, OnPrem, etc.):
• KServe Version: 0.11.1

[rachitchauhan43]

/assign @rachitchauhan43