Merge branch 'docs-rollout-resource-type' into 'master'

Add rollout type to variables list.

See merge request gitlab-org/gitlab-ce!27757

doc/topics/autodevops/index.md

@@ -770,6 +770,7 @@ also be customized, and you can easily use a [custom buildpack](#custom-buildpac
 | `PERFORMANCE_DISABLED`       | From GitLab 11.0, this variable can be used to disable the `performance` job. If the variable is present, the job will not be created. |
 | `K8S_SECRET_*`               | From GitLab 11.7, any variable prefixed with [`K8S_SECRET_`](#application-secret-variables) will be made available by Auto DevOps as environment variables to the deployed application. |
 | `KUBE_INGRESS_BASE_DOMAIN`   | From GitLab 11.8, this variable can be used to set a domain per cluster. See [cluster domains](../../user/project/clusters/index.md#base-domain) for more information. |
+| `ROLLOUT_RESOURCE_TYPE`     | From GitLab 11.9, this variable allows specification of the resource type being deployed when using a custom helm chart. Default value is `deployment`. |
 | `HELM_UPGRADE_EXTRA_ARGS`   | From GitLab 11.11, this variable allows extra arguments in `helm` commands when deploying the application. Note that using quotes will not prevent word splitting. |
 
 TIP: **Tip:**