make PodIP.IP and HostIP.IP required.

Fields used as map keys must be required or defaulted when used in a CRD schema.

see kubernetes/kubernetes#124540

Signed-off-by: Lan Liang <gcslyp@gmail.com>

Kubernetes-commit: 3ba8e9e80ee3123d5936fdfb95095418008a8756

core/v1/types.go

@@ -4340,13 +4340,15 @@ type PodDNSConfigOption struct {
 // PodIP represents a single IP address allocated to the pod.
 type PodIP struct {
 	// IP is the IP address assigned to the pod
-	IP string `json:"ip,omitempty" protobuf:"bytes,1,opt,name=ip"`
+	// +required
+	IP string `json:"ip" protobuf:"bytes,1,opt,name=ip"`
 }
 
 // HostIP represents a single IP address allocated to the host.
 type HostIP struct {
 	// IP is the IP address assigned to the host
-	IP string `json:"ip,omitempty" protobuf:"bytes,1,opt,name=ip"`
+	// +required
+	IP string `json:"ip" protobuf:"bytes,1,opt,name=ip"`
 }
 
 // EphemeralContainerCommon is a copy of all fields in Container to be inlined in