Update docs

lib/strategy/kubernetes.ex

@@ -25,6 +25,7 @@ defmodule Cluster.Strategy.Kubernetes do
      - `:kubernetes_selector`
      - `:kubernetes_service_name`
      - `:kubernetes_ip_lookup_mode`
+     - `:kubernetes_resource_version`
      - `:mode`
 
   ## Getting `<basename>`
@@ -70,6 +71,12 @@ defmodule Cluster.Strategy.Kubernetes do
 
   Then, this strategy will fetch the IP of all pods with that label and attempt to connect.
 
+  ### `kubernetes_resource_version` option
+
+  When setting this value, this strategy will use given resource version value to fetch k8s resources,
+  where each modification of the resource increments the resource version.
+
+  If set to `0` kubernetes will use cached version, that may be outdated.
 
   ### `:mode` option