stdlib: update gcp to use secrets

Signed-off-by: Andrea Luzzardi <aluzzardi@gmail.com>

tests/stdlib/gcp/gke/.dagger/env/default/plan/gke.cue

@@ -0,0 +1,32 @@
+package gke
+
+import (
+	"dagger.io/gcp"
+	"dagger.io/gcp/gke"
+	"dagger.io/kubernetes"
+	"dagger.io/dagger/op"
+)
+
+TestConfig: gcpConfig: gcp.#Config
+
+TestCluster: gke.#KubeConfig & {
+	config:      TestConfig.gcpConfig
+	clusterName: "test-cluster"
+}
+
+TestGKE: #up: [
+	op.#Load & {
+		from: kubernetes.#Kubectl
+	},
+
+	op.#WriteFile & {
+		dest:    "/kubeconfig"
+		content: TestCluster.kubeconfig
+	},
+
+	op.#Exec & {
+		always: true
+		args: ["kubectl", "get", "nodes"]
+		env: KUBECONFIG: "/kubeconfig"
+	},
+]