fix(config): use the correct schema in the kube config file

[aazon]

Currently, there are a few issues when I want the otc-auth tool to obtain CCE credentials and output them so that I can forward the output into a file:

otc-auth cce get-kube-config \
    --cluster "${TF_VAR_context}-${TF_VAR_stage}" \
    --days-valid 7 \
    --output \
> kubeconfig.yaml

1. The otc-auth outputs the config file to STDERR, which already may contain log messages. That makes the kubeconfig.yaml not readable by kubectl.
2. Even if there are no logs in the STDERR, the format of the generated JSON(YAML) is incompatible with the kubectl tool.

This pull request solves both of the above issues.

[Ninja243]

lgtm!