Correct button name to add k8s cluster [docs]

doc/user/project/clusters/add_eks_clusters.md

@@ -77,7 +77,7 @@ To create and add a new Kubernetes cluster to your project, group, or instance:
    - Project's **Operations > Kubernetes** page, for a project-level cluster.
    - Group's **Kubernetes** page, for a group-level cluster.
    - **Admin Area > Kubernetes**, for an instance-level cluster.
-1. Click **Add Kubernetes cluster**.
+1. Click **Integrate with a cluster certificate**.
 1. Under the **Create new cluster** tab, click **Amazon EKS** to display an
    `Account ID` and `External ID` needed for later steps.
 1. In the [IAM Management Console](https://console.aws.amazon.com/iam/home), create an IAM policy:

doc/user/project/clusters/add_gke_clusters.md

@@ -49,7 +49,7 @@ To create and add a new Kubernetes cluster to your project, group, or instance:
    - Project's **{cloud-gear}** **Operations > Kubernetes** page, for a project-level cluster.
    - Group's **{cloud-gear}** **Kubernetes** page, for a group-level cluster.
    - **Admin Area >** **{cloud-gear}** **Kubernetes** page, for an instance-level cluster.
-1. Click **Add Kubernetes cluster**.
+1. Click **Integrate with a cluster certificate**.
 1. Under the **Create new cluster** tab, click **Google GKE**.
 1. Connect your Google account if you haven't done already by clicking the
    **Sign in with Google** button.

doc/user/project/clusters/add_remove_clusters.md

@@ -147,7 +147,7 @@ Amazon Elastic Kubernetes Service (EKS) at the project, group, or instance level
    - Project's **{cloud-gear}** **Operations > Kubernetes** page, for a project-level cluster.
    - Group's **{cloud-gear}** **Kubernetes** page, for a group-level cluster.
    - **Admin Area >** **{cloud-gear}** **Kubernetes** page, for an instance-level cluster.
-1. Click **Add Kubernetes cluster**.
+1. Click **Integrate with a cluster certificate**.
 1. Click the **Create new cluster** tab.
 1. Click either **Amazon EKS** or **Google GKE**, and follow the instructions for your desired service:
    - [Amazon EKS](add_eks_clusters.md#new-eks-cluster).