gitlab update script broken

[yayayayaka]

Describe the bug

The gitlab update.py script depends on nix-universal-prefetch, which was removed by 578d7e7 in #321436.

Steps To Reproduce

Steps to reproduce the behavior:

1. cd pkgs/applications/version-management/gitlab; ./update.py update-all

Expected behavior

The update scripts succeeds.

Notify maintainers

(myself)

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[Mic92]

Also looks like nix-update could be used here.

[Mic92]

Ok. looks like switching to nix-update would require some other major refactoring because the update.py writes out some json file out. But here is a simpler approach: #322179