Document that GKE master_auth key is an array (#617)
Document that GKE master_auth key is an array (#617)

* Document that GKE master_auth key is an array

This resolves https://github.com/hashicorp/terraform/issues/16417 and is a follow up to https://github.com/hashicorp/terraform/issues/14073

* Update container_cluster.html.markdown

* Update container_cluster.html.markdown

* Update container_cluster.html.markdown

nickithewatt/terraform-provider-google,hashicorp/terraform-provider-google,nickithewatt/terraform-provider-google,hashicorp/terraform-provider-google-beta,drebes/terraform-provider-google,hashicorp/terraform-provider-google,rosbo/terraform-provider-google,terraform-providers/terraform-provider-google,ubschmidt2/terraform-provider-google,drebes/terraform-provider-google,hashicorp/terraform-provider-google-beta,ubschmidt2/terraform-provider-google,drebes/terraform-provider-google,selmanj/terraform-provider-google,terraform-providers/terraform-provider-google,rosbo/terraform-provider-google,selmanj/terraform-provider-google,ubschmidt2/terraform-provider-google,nickithewatt/terraform-provider-google,terraform-providers/terraform-provider-google,drebes/terraform-provider-google,hashicorp/terraform-provider-google-beta,hashicorp/terraform-provider-google,terraform-providers/terraform-provider-google,ubschmidt2/terraform-provider-google,rosbo/terraform-provider-google,terraform-providers/terraform-provider-google,selmanj/terraform-provider-google,hashicorp/terraform-provider-google-beta,hashicorp/terraform-provider-google,rosbo/terraform-provider-google