this mirrors a change in the nixpkgs definition: the nix-update script
has a hardcoded list of attributes it will update. We can re-use one of
them to make it update mattermost's web frontend at the same time as it
updates mattermost itself.
The list of attribute names is here:
https://github.com/Mic92/nix-update/tree/1.3.1?tab=readme-ov-file#features
original nixpkgs commit by numinit was
1451a58a57e1bd1592460268bdde30cf72923010
1451a58a57
