common: update google-auto-auth to 0.6.0 (#2162)
common: update google-auto-auth to 0.6.0 (#2162)


GoogleCloudPlatform/gcloud-node,callmehiphop/gcloud-node,googleapis/google-cloud-node,GoogleCloudPlatform/gcloud-node,jgeewax/gcloud-node,googleapis/google-cloud-node,googleapis/google-cloud-node,googleapis/google-cloud-node,callmehiphop/gcloud-node,GoogleCloudPlatform/gcloud-node,jgeewax/gcloud-node