fix: GITLAB_USERNAME_CHANGE Not effective

[jinjianming]

Users can still modify their usernames after adding 'GITLAB-USERNAME-CHANGE'I confirm that I have restarted after making the modifications

[kkimurak]

It is expected behavior. The "Full name" can be changed even GITLAB_USERNAME_CHANGE is set to false. As far as I known, there is no way to disallow user to edit it.
The parameter GITLAB_USERNAME_CHANGE only affect to user name that will (not) be shown in "Account" settings.

[kkimurak]

@jinjianming I'm not sure what you're confusing, but I'll try to explain it more clearly:

• GITLAB_USERNAME_CHANGE restricts user to not to modify "User name". For me on github, it is "kkimurak" and used when mentioning to user, for example. If the parameter GITLAB_USERNAME_CHANGE is set to false, corresponding setting will not be shown in "Edit profile" page.
• What you are surrounding in the image is "Full name". For me on github, it is "Kazunori Kimura". This can be modified even GITLAB_USERNAME_CHANGE is set to false