Merge branch 'docs-gitlab-supports-kubernetes-1-16' into 'master'

Update the Kubernetes version list to include 1.16

See merge request gitlab-org/gitlab!33237

doc/user/project/clusters/index.md

@@ -46,6 +46,7 @@ GitLab is committed to support at least two production-ready Kubernetes minor ve
 
 Currently, GitLab supports the following Kubernetes versions:
 
+- 1.16
 - 1.15
 - 1.14
 - 1.13 (deprecated, support ends on November 22, 2020)