require specific ruff version

[jepler]

I was having trouble with pre-commit always finding files to change, because the ruff run during two different steps of pre-commit were different.

Installing the requirements with pip install -r requirements-dev.txt didn't resolve the problem, because the ruff version was not pinned. So, pin it now.

[dhalbert]

Makes sense , since pre-commit-config.yaml requires explicit versions.

[tannewt]

Thank you! I may have run into this too.