Failure to parse AWS generated kube config

[seanamosw]

I saw the initial implementation for supporting the user/exec config was done in #359

However, it appears that it is still unable to parse the exec/env section.

This appears to be how the model is specified in https://github.com/kubernetes-client/csharp/blob/master/src/KubernetesClient/KubeConfigModels/ExternalExecution.cs

        [YamlMember(Alias = "env")]
        public IDictionary<string, string> EnvironmentVariables { get; set; }

That would parse yaml with this format:

env:
  name1: value1
  name2: value2

However the actual format is:

env:
   - name: name1
     value: value1
   - name: name2
     value: value2

I believe this needs to at least be changed to something like this:

        [YamlMember(Alias = "env")]
        public IList<IDictionary<string, string>> EnvironmentVariables { get; set; }

Might want to further change it to something like:

        public IList<NameValuePair> EnvironmentVariables { get; set; }

[brendandburns]

We'd be happy to have a PR to fix this.

Thanks!