Avoid Passing nil in Exec Call

[peixian]

Currently, if you're using GKE and an updated Kube cluster with the gke-auth-plugin (https://cloud.google.com/blog/products/containers-kubernetes/kubectl-auth-changes-in-gke), it'll write a config file that looks like

users: 
- name: <CLUSTER>
  user:
    exec:
      apiVersion: client.authentication.k8s.io/v1beta1
      command: /Users/peixian/miniconda3/envs/gcloud/share/google-cloud-sdk-390.0.0-0/bin/gke-gcloud-auth-plugin
      installHint: Install gke-gcloud-auth-plugin for use with kubectl by following
        https://cloud.google.com/blog/products/containers-kubernetes/kubectl-auth-changes-in-gke
      provideClusterInfo: true

This doesn't set an args, which causes a nil error when checking config.args. This PR just adds a null default for cases like this.

Requirements for all pull requests

• Entry in CHANGELOG.md was created

Additional requirements for new features

• New unit tests were created
• New integration tests were created
• PR description contains a link to the according kubernetes documentation

[mruoss]

Oh well yes, I see the problem. However, I'd rather define default values inside defstruct instead:

  defstruct [:command, :env, args: []]

You wanna update your PR or shall I commit that change?

[mruoss]

Never mind. Fixed in 2f0525e

[peixian]

excellent, thanks!