thoughts on adding nightly vrcx

[TayouVR]

as title states. release package is here: https://github.com/NixOS/nixpkgs/tree/master/pkgs/by-name/vr/vrcx

nightly releases are published every few days, sometimes daily, here https://github.com/Natsumi-sama/VRCX/releases

I can try to PR it myself later, if there is interest

[nanoyaki]

We could also give it a shot at trying to package it from source. Generally I personally think nightly VRCX sounds like a good addition to this repo.

[Scrumplex]

Only issue I can foresee, is that nvfetcher doesn't support updating deps.json. In fact it only really supports generating cargoDeps and otherwise extracting files from repos. I thought about moving to nix-update (or updateScripts in general) using custom scripts, but haven't worked on that yet