Merge branch 'mattl-gitshell-fixes' into 'master'

Updates the docs to require GitLab Shell 4.0.3

See merge request !8050

doc/update/8.13-to-8.14.md

@@ -72,7 +72,7 @@ sudo -u git -H git checkout 8-14-stable-ee
 ```bash
 cd /home/git/gitlab-shell
 sudo -u git -H git fetch --all --tags
-sudo -u git -H git checkout v4.0.0
+sudo -u git -H git checkout v4.0.3
 ```
 
 ### 6. Update gitlab-workhorse