Bump pyproject-build-systems from 04e9c18 to b6e74f4

Bumps [pyproject-build-systems](https://github.com/pyproject-nix/build-system-pkgs) from `04e9c18` to `b6e74f4`.
- [Commits](pyproject-nix/build-system-pkgs@04e9c18...b6e74f4)

---
updated-dependencies:
- dependency-name: pyproject-build-systems
  dependency-version: b6e74f433b02fa4b8a7965ee24680f4867e2926f
  dependency-type: direct:production
...

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Author: dependabot[bot]