Update Gitlab

[lanrat]

It looks like Gitlab is on a monthly release cycle, a new version is released on the 22nd of every month. I think that every month may be a but much for us. But we should create an update strategy. Bi-monthly, quarterly?

We are currently on 6.3-stable, the latest is 6.8-stable.
We should also make a good deploy mechanism. @lcycon any progress on this?

For reference:
Upgrade guide: https://gitlab.com/gitlab-org/gitlab-ce/tree/master/doc/update
Change log: https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG

The same applies to gitlab-shell.