Make support workflow links absolute

Fixes https://gitlab.com/gitlab-com/www-gitlab-com/issues/1258

The update of middleman in https://gitlab.com/gitlab-com/www-gitlab-com/commit/aab9676aea985eb8ef36ab1b3d6eef000acbb488
broke the link_to method for absolute links. Simple fix is to add /
4 jobs for absolute-links in 14 minutes and 33 seconds (queued for 29 seconds)