fix(tvix): fix `cargo test` for `nix_oracle` r/6929

As described in https://b.tvl.fyi/issues/313, the `nix_oracle` tests
currently fail if run without Nix 2.3 in `$PATH`.

This is not a problem for people running Nix 2.3 on their systems, and
neither is it for the tests running inside Nix derivations itself (as we
hardcode Nix 2.3 there), but for interactive `cargo test` runs, either
using `mg shell //tvix:shell`, or `nix-shell` (from the tvix workspace)
it currently is broken.

Adding Nix 2.3 to the shell fixes that.

Change-Id: Idbe01aa92d63eb1a3dab5797b9be5eba1e8d7f7a
Reviewed-on: https://cl.tvl.fyi/c/depot/+/9907
Autosubmit: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>

0 files changed, 0 insertions, 0 deletions