Update kubernetes managed apps helm to v2.16.1

lib/gitlab/kubernetes/helm.rb

@@ -3,7 +3,7 @@
 module Gitlab
   module Kubernetes
     module Helm
-      HELM_VERSION = '2.15.1'
+      HELM_VERSION = '2.16.1'
       KUBECTL_VERSION = '1.13.12'
       NAMESPACE = 'gitlab-managed-apps'
       SERVICE_ACCOUNT = 'tiller'

spec/lib/gitlab/kubernetes/helm/pod_spec.rb

@@ -30,7 +30,7 @@ describe Gitlab::Kubernetes::Helm::Pod do
       it 'generates the appropriate specifications for the container' do
         container = subject.generate.spec.containers.first
         expect(container.name).to eq('helm')
-        expect(container.image).to eq('registry.gitlab.com/gitlab-org/cluster-integration/helm-install-image/releases/2.15.1-kube-1.13.12')
+        expect(container.image).to eq('registry.gitlab.com/gitlab-org/cluster-integration/helm-install-image/releases/2.16.1-kube-1.13.12')
         expect(container.env.count).to eq(3)
         expect(container.env.map(&:name)).to match_array([:HELM_VERSION, :TILLER_NAMESPACE, :COMMAND_SCRIPT])
         expect(container.command).to match_array(["/bin/sh"])