kyverno: [BUG] `spec.failurePolicy` to use lower-case values

Software version numbers State the version numbers of applications involved in the bug.

• Kubernetes version: N/A
• Kubernetes platform (if applicable; ex., EKS, GKE, OpenShift): N/A
• Kyverno version: 1.6.0-rc3

Describe the bug spec.failurePolicy states/requires values which do not follow conventional value formatting (initial letter upper case).

failurePolicy        <string>
     FailurePolicy defines how unrecognized errors from the admission endpoint
     are handled. Rules within the same policy share the same failure behavior.
     Allowed values are Ignore or Fail. Defaults to Fail.

Expected behavior Values of the failurePolicy field are lower case or follow camel case convention. Need to update the CRDs so explain also reflects this.