Update Helm Tiller used by gitlab-managed-apps to 2.7.2

changelogs/unreleased/49830-use-helm-272.yml

+---
+title: Use Helm 2.7.2 for GitLab Managed Apps
+merge_request: 20956
+author:
+type: changed

lib/gitlab/kubernetes/helm.rb

 module Gitlab
   module Kubernetes
     module Helm
-      HELM_VERSION = '2.7.0'.freeze
+      HELM_VERSION = '2.7.2'.freeze
       NAMESPACE = 'gitlab-managed-apps'.freeze
     end
   end

spec/support/shared_examples/helm_generated_script.rb

@@ -7,7 +7,7 @@ shared_examples 'helm commands' do
          echo http://mirror.clarkson.edu/alpine/v$ALPINE_VERSION/main >> /etc/apk/repositories
          echo http://mirror1.hs-esslingen.de/pub/Mirrors/alpine/v$ALPINE_VERSION/main >> /etc/apk/repositories
          apk add -U wget ca-certificates openssl >/dev/null
-         wget -q -O - https://kubernetes-helm.storage.googleapis.com/helm-v2.7.0-linux-amd64.tar.gz | tar zxC /tmp >/dev/null
+         wget -q -O - https://kubernetes-helm.storage.googleapis.com/helm-v2.7.2-linux-amd64.tar.gz | tar zxC /tmp >/dev/null
          mv /tmp/linux-amd64/helm /usr/bin/
       EOS
     end