Document that when updating using a Helm chart 'helm repo update' needs to be run before the 'helm upgrade ...' command.  

With an updated list of the images you need to change when switching to
the CE version.

Originally submitted at
https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/6101

.

Signed-off-by: Rémy Coutable <remy@rymai.me>

Originally submitted at
https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/6617

.

Signed-off-by: Rémy Coutable <remy@rymai.me>

The pngquant tool was used https://pngquant.org, and particularly, the
following command:

        /usr/bin/pngquant -f --skip-if-larger --ext .png --speed 1 image.png

Before: 47584K
After : 34924K

"/home/git/repositories" in arguments causes Gitaly installation to fail

The nip.io service was being linked to twice in the note on cert
requests.

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>