Update kindest/node Docker tag to v1.31.6 (#470)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

hack/config/kind-config.yaml

@@ -2,7 +2,7 @@ apiVersion: kind.x-k8s.io/v1alpha4
 kind: Cluster
 nodes:
 - role: control-plane
-  image: kindest/node:v1.31.4
+  image: kindest/node:v1.31.6
   extraPortMappings:
   # ingress-nginx
   - containerPort: 30888