Add Powershell support to justfile

[nathanjmcdougall]

[ ] Add tests for the change. In general, aim for full test coverage at the Python level. Rust tests are optional.
[ ] Add any appropriate documentation.
[x] Add a summary of changes to CHANGELOG.rst.
[ ] Add your name to AUTHORS.rst.
[x] Run just full-check.

I've tested and it works locally when running via PowerShell from within VS Code, whereas it didn't before. Fixes #273

[codspeed-hq]

CodSpeed Performance Report

Merging #277 will not alter performance

_{Comparing nathanjmcdougall:fix/add-powershell-support-to-justfile (12689e7) with main (82ebd22)}

Summary

✅ 26 untouched
⏩ 23 skipped¹

Footnotes

1. 23 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[seddonym]

Thanks for adding!