Document `include` on gitlab-ci.yml does not support HTTP authentication
include
on gitlab-ci.yml
does not support HTTP authentication out of the box for remote files, we need to include this in the documentation as it can cause some confusion (see https://gitlab.com/gitlab-org/gitlab-ce/issues/43492)
Although there's a workaround for this at the moment, also mentioned in https://gitlab.com/gitlab-org/gitlab-ce/issues/43492#note_60250268