tvix: check generated crate2nix config on CI runs

Opened by tazjin at 2022-12-12T11·05+00

We should have an extra step that checks whether the crate2nix config is up-to-date. This is difficult to do in a derivation, but should be fine using an extra step.

Suggested by flokli on cl/7538.

  1. Note that crate2nix generation is apparently unstable:

    tazjin at 2022-12-12T11·49+00