AdvancedStatefulSet CRD won't load in GKE v1.16.9 :: spec.preserveUnknownFields: Invalid value: true

Bug Report

What version of Kubernetes are you using?

kubectl version
Client Version: version.Info{Major:"1", Minor:"18", GitVersion:"v1.18.4", GitCommit:"c96aede7b5205121079932896c4ad89bb93260af", GitTreeState:"clean", BuildDate:"2020-06-17T11:41:22Z", GoVersion:"go1.13.9", Compiler:"gc", Platform:"linux/amd64"}
Server Version: version.Info{Major:"1", Minor:"16+", GitVersion:"v1.16.9-gke.2", GitCommit:"4751ff766b3f6dbf6c6a63394a909e8108e89744", GitTreeState:"clean", BuildDate:"2020-05-08T16:44:50Z", GoVersion:"go1.13.9b4", Compiler:"gc", Platform:"linux/amd64"}

What version of TiDB Operator are you using?

v1.1.2

What storage classes exist in the Kubernetes cluster and what are used for PD/TiKV pods?

$ kubectl get sc
NAME PROVISIONER AGE
managed-premium kubernetes.io/gce-pd 339d
standard (default) kubernetes.io/gce-pd 339d

What's the status of the TiDB cluster pods?

What did you do?

From instructions on https://docs.pingcap.com/tidb-in-kubernetes/v1.1/advanced-statefulset page,

kubectl apply -f https://raw.githubusercontent.com/pingcap/tidb-operator/master/manifests/advanced-statefulset-crd.v1.yaml --validate=false
The CustomResourceDefinition "statefulsets.apps.pingcap.com" is invalid: spec.preserveUnknownFields: Invalid value: true: must be false in order to use defaults in the schema

What did you expect to see?

expected CRD to load

What did you see instead?
The CustomResourceDefinition "statefulsets.apps.pingcap.com" is invalid: spec.preserveUnknownFields: Invalid value: true: must be false in order to use defaults in the schema

Inspect manifests/advanced-statefulset-crd.v1.yaml, linked from the AdvancedStatefulSet documentation, and reproduce the kubectl apply command against Kubernetes v1.16. Confirm which CRD schema setting causes the preserveUnknownFields validation error, then verify that the corrected manifest loads successfully on the reported GKE version.