Merge branch 'helm-2.12.3' into 'master'

Bump Helm and kubectl in Auto DevOps

See merge request gitlab-org/gitlab-ce!25072

changelogs/unreleased/helm-2-12-3.yml

+---
+title: Bump Helm and kubectl in Auto DevOps to 2.12.3 and 1.11.7 respectively
+merge_request: 25072
+author:
+type: other

lib/gitlab/ci/templates/Auto-DevOps.gitlab-ci.yml

@@ -49,8 +49,8 @@ variables:
   POSTGRES_ENABLED: "true"
   POSTGRES_DB: $CI_ENVIRONMENT_SLUG
 
-  KUBERNETES_VERSION: 1.11.6
-  HELM_VERSION: 2.12.2
+  KUBERNETES_VERSION: 1.11.7
+  HELM_VERSION: 2.12.3
 
   DOCKER_DRIVER: overlay2