MountVolume.SetUp failed for volume "cert" : secret "kfserving-webhook-server-cert" not found

/kind bug

What steps did you take and what happened: I have installed kfserving as mentioned here https://github.com/kubeflow/kfserving#install-kfserving. But kfserving-controller-manager pod is stuck in container creating state with an error MountVolume.SetUp failed for volume "cert" : secret "kfserving-webhook-server-cert" not found

$ kubectl get pod -n kfserving-system
NAME                                        READY   STATUS              RESTARTS   AGE
kfserving-controller-manager-0              0/2     ContainerCreating   0          131m
kfserving-models-web-app-84d5d66954-cckfc   1/1     Running             0          131m

$ kubectl get secret -n kfserving-system
NAME                                   TYPE                                  DATA   AGE
default-token-bvcxz                    kubernetes.io/service-account-token   3      139m
kfserving-models-web-app-token-gfzrc   kubernetes.io/service-account-token   3      139m
kfserving-webhook-server-secret        Opaque                                0      139m

What did you expect to happen:

Expected kfserving-controller-manager-0 to be in running state.

Environment:

• Istio Version: 1.9.3
• Knative Version: v0.23.0
• KFServing Version: v0.6.0
• Kfdef:[k8s_istio/istio_dex/gcp_basic_auth/gcp_iap/aws/aws_cognito/ibm]
• Kubernetes version: v1.19.6
• OS (e.g. from /etc/os-release): Amazon Linux 2