powerstat: 0.02.15 -> 0.02.16

Semi-automatic update generated by https://github.com/ryantm/nixpkgs-update tools.

This update was made based on information from https://repology.org/metapackage/powerstat/versions.

These checks were done:

- built on NixOS
- /nix/store/r8r2fb581gxng6pkwyvbssyl3w21f2pg-powerstat-0.02.16/bin/powerstat passed the binary check.
- 1 of 1 passed binary check by having a zero exit code.
- 0 of 1 passed binary check by having the new version present in output.
- found 0.02.16 with grep in /nix/store/r8r2fb581gxng6pkwyvbssyl3w21f2pg-powerstat-0.02.16
- directory tree listing: https://gist.github.com/07ed4981848777e18cca2c072d0fb30c
- du listing: https://gist.github.com/5766491662635d4a960a7cd3a4911db0