Noted the change to the gitlab-shell config.yml, which changed substantially...

Noted the change to the gitlab-shell config.yml, which changed substantially in recent versions and broke the upgrade when not updated

doc/update/6.2-to-6.3.md

@@ -24,7 +24,7 @@ sudo -u git -H git fetch
 sudo -u git -H git checkout 6-3-stable
 ```
 
-### 3. Update gitlab-shell
+### 3. Update gitlab-shell (and its config)
 
 ```bash
 cd /home/git/gitlab-shell
@@ -32,6 +32,8 @@ sudo -u git -H git fetch
 sudo -u git -H git checkout v1.7.9 # Addresses multiple critical security vulnerabilities
 ```
 
+The Gitlab-shell config changed recently, so check for config file changes and make `/home/git/gitlab-shell/config.yml` the same as https://github.com/gitlabhq/gitlab-shell/blob/master/config.yml.example
+
 ### 4. Install additional packages
 
 ```bash