Fix helm for Kubernetes 1.16.2 (kubernetes-sigs#5332)

Since upgrading k8s beyond 1.16.0 version, helm init does
no longer work with helm < 2.16.0 due to
helm/helm#6374

This PR closes issue kubernetes-sigs#5331

roles/download/defaults/main.yml

@@ -301,7 +301,7 @@ test_image_repo: "{{ docker_image_repo }}/library/busybox"
 test_image_tag: latest
 busybox_image_repo: "{{ docker_image_repo }}/library/busybox"
 busybox_image_tag: 1.29.2
-helm_version: "v2.14.3"
+helm_version: "v2.16.0"
 helm_image_repo: "{{ docker_image_repo }}/lachlanevenson/k8s-helm"
 helm_image_tag: "{{ helm_version }}"
 tiller_image_repo: "{{ gcr_image_repo }}/kubernetes-helm/tiller"