Added service account field to kubernetes steps

.drone.yml

@@ -93,12 +93,15 @@ steps:
 
   - name: ensure namespace
     image: bitnami/kubectl:latest
+    settings:
+      serviceAccountName: droneci-sa
     commands:
       - kubectl create namespace sampleapi --dry-run=client -o yaml | kubectl apply -f -
 
   - name: deploy
     image: danielgormly/drone-plugin-kube:0.0.1
     settings:
+      serviceAccountName: droneci-sa
       template: ./manifests/deploy.yml
       namespace: sampleapi
       ca: