Adding 16.10.1, 16.9.3, 16.8.5 blog post
Add blog post for 16.10.1, 16.9.3, 16.8.5 patch release.
- Security release issue: https://gitlab.com/gitlab-org/gitlab/-/issues/446238
- Appsec security release checklist: https://gitlab.com/gitlab-org/gitlab/-/issues/451923
- Release communications issue: https://gitlab.com/gitlab-com/gl-security/security-communications/communications/-/issues/588
Copied from https://gitlab.com/gitlab-org/security/www-gitlab-com/-/merge_requests/191