update README

Author: Saed SayedAhmed

charts/nginx-ingress/README.md

@@ -313,6 +313,7 @@ The following tables lists the configurable parameters of the NGINX Ingress Cont
 |`controller.minReadySeconds` | Specifies the minimum number of seconds for which a newly created Pod should be ready without any of its containers crashing, for it to be considered available. [docs](https://kubernetes.io/docs/concepts/workloads/controllers/deployment/#min-ready-seconds) | 0 |
 |`controller.autoscaling.enabled` | Enables HorizontalPodAutoscaling. | false |
 |`controller.autoscaling.annotations` | The annotations of the Ingress Controller HorizontalPodAutoscaler. | {} |
+|`controller.autoscaling.behavior` | Behavior configuration for the HPA. | {} |
 |`controller.autoscaling.minReplicas` | Minimum number of replicas for the HPA. | 1 |
 |`controller.autoscaling.maxReplicas` | Maximum number of replicas for the HPA. | 3 |
 |`controller.autoscaling.targetCPUUtilizationPercentage` | The target CPU utilization percentage. | 50 |