Following the steps in this article, I achieved the desired results by adding the rate limit plugin in my kongo ingress. To do so, first, update / create your ingress definition and add the annotations defined below:

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: func
  namespace: default
  annotations:
    kubernetes.io/ingress.class: kong   # <-- THIS
    plugins.konghq.com: http-ratelimit  # <-- THIS
spec:
...

After, to finally set the rate-limit, use this definition and apply it in your kubernetes cluster:

apiVersion: configuration.konghq.com/v1
kind: KongPlugin
metadata:
  name: http-ratelimit
  namespace: default
config:
  policy: local
  second: 1
plugin: rate-limiting 

This will create a restriction of 1 request per second in your ingress. If you want anything different, just change the config section with your own configuration. Check the plugin's documentation for all possible configurations.