Doc linter fix
Doc linter fix

- Use Omnibus GitLab instead of GitLab Omnibus

Signed-off-by: Robert Marshall <0465b3b4f3ae0103ad50d09ff86a3523700a2979@gitlab.com>

gitlabhq/omnibus-gitlab,gitlabhq/omnibus-gitlab,gitlabhq/omnibus-gitlab,gitlabhq/omnibus-gitlab