Write how to setup dns discovery in Readme file

[andrey-gava]

Hello!

Despite fixed bug mentioned in #58 I still cant figure out how to make it work.
I tried to install last available chart version 3.5.4 with all default values except that I edited provided values.yaml
and set it like this

     kubernetes:
            enabled: true
            service-name: 
            service-dns: ${serviceName}
            namespace: ${namespace}

but hazelcast pods trow the same error in logs:
Exception in thread "main" com.hazelcast.config.InvalidConfigurationException: The configuration entry under hazelcast/network/join/kubernetes/service-name is null. Please check if the provided YAML configuration is well-indented and no blocks started without sub-nodes.
And no mater how I try to configure it, with 'null' value or even without 'service-name: ' string it still errors in logs.
Maybe I do it in wrong way?
And by the way when used with dns discovery mode do I set only rbac.create=false or full list like this:

rbac.create=false
serviceAccount.create=false
serviceAccount.automountToken=false

Cant someone put description on this to Readme file @leszko ?

[leszko]

I update README in #187

Btw. here's the configuration you need:

hazelcast:
  yaml:
    hazelcast:
      network:
        join:
          kubernetes:
            service-dns: "${serviceName}.${namespace}.svc.cluster.local"
            service-name: ''
            namespace: ''
rbac:
  create: false