Nix build failure: stardust-xr-server requires rustc 1.75 or newer

[Sntx626]

When trying to build the package with:

nix build

I get the error:

error: package `stardust-xr-server v0.44.0 (/build/stardust-xr-server-source)` cannot be built because it requires rustc 1.75 or newer, while the currently active rustc version is 1.71.1

How to fix:

nix flake update

I'll create a PR with an updated flake.lock.

However I think that at some point we should think about a CI/CD pipeline that auto-updates the flake.lock.