Update docs as GKE cluster creation label has changed from "project ID" to "project"
We changed the label of the GKE cluster creation form from "project ID" to "project" recently (https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/19528) as the automatic parameter fetching was showing the project names.
We need to update the docs accordingly:
it seems we must update the docs for this as they still state The ID of the project you created in your GCP console that will host the Kubernetes cluster. This must not be confused with the project name https://docs.gitlab.com/ee/user/project/clusters/#adding-and-creating-a-new-gke-cluster-via-gitlab