Update the installation docs to state that GitLab uses Go 1.8
Currently, the GitLab-CE documentation states that GitLab requires Go v1.5.3 in order to compile gitlab-workhorse
.
https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/install/installation.md#3-go
However, the Go components now need Go 1.8. See https://gitlab.com/gitlab-org/omnibus-gitlab/issues/2279
While we're doing this, it's probably also worth updating the documentation to mention the other components written in Golang (not just workhorse):
- Pages
- es-git-go
- workhorse
- gitaly
References: