Adding 16.5.1, 16.4.2, 16.3.6 blog post
Add blog post for 16.5.1, 16.4.2, 16.3.6 patch release.
-
Complete any sections of the blog post that have TODO in their content.
Security release tracking issue: https://gitlab.com/gitlab-org/gitlab/-/issues/426612
Copied from https://gitlab.com/gitlab-org/security/www-gitlab-com/-/merge_requests/165