build(deps): bump the nix group across 1 directory with 2 updates

Bumps the nix group with 2 updates in the / directory: [nixify](https://github.com/rvolosatovs/nixify) and [nixpkgs-unstable](https://github.com/NixOS/nixpkgs).


Updates `nixify` from `e4eb22b` to `4d6b964`
- [Release notes](https://github.com/rvolosatovs/nixify/releases)
- [Commits](rvolosatovs/nixify@e4eb22b...4d6b964)

Updates `nixpkgs-unstable` from `5545adf` to `c7def04`
- [Commits](NixOS/nixpkgs@5545adf...c7def04)

---
updated-dependencies:
- dependency-name: nixify
  dependency-version: 4d6b9646690c3f515ec94fc8a0f3d4ad490206ee
  dependency-type: direct:production
  dependency-group: nix
- dependency-name: nixpkgs-unstable
  dependency-version: c7def046b9a883d46974757852106483d741586f
  dependency-type: direct:production
  dependency-group: nix
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]