sudo user is git, not gitlab, not gitlab_ci

[ci skip]

doc/update/7.14-to-8.0.md

@@ -99,8 +99,8 @@ Don't store it in the same place as your database backups,
 otherwise your secrets are exposed if one of your backups is compromised.
 
 ```
-sudo -u gitlab -H cp config/secrets.yml.example config/secrets.yml
-sudo -u gitlab -H chmod 0600 config/secrets.yml
+sudo -u git -H cp config/secrets.yml.example config/secrets.yml
+sudo -u git -H chmod 0600 config/secrets.yml
 ```
 
 ### 7. Install libs, migrations, etc.