chore(deps): bump nixpkgs from eef00df to d99b013 (#19)

Bumps [nixpkgs](https://github.com/NixOS/nixpkgs) from `eef00df` to `d99b013`.
- [Commits](NixOS/nixpkgs@eef00df...d99b013)

---
updated-dependencies:
- dependency-name: nixpkgs
  dependency-version: d99b013d5d1931ad77fe3912ed218170dec5d9a4
  dependency-type: direct:production
...

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