chore(deps): bump nixpkgs from 0726a0e to 15f4ee4 (#12)

Bumps [nixpkgs](https://github.com/NixOS/nixpkgs) from `0726a0e` to `15f4ee4`.
- [Commits](NixOS/nixpkgs@0726a0e...15f4ee4)

---
updated-dependencies:
- dependency-name: nixpkgs
  dependency-version: 15f4ee454b1dce334612fa6843b3e05cf546efab
  dependency-type: direct:production
...

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Author: dependabot[bot]