lintstagedrc.js failes on Windows

• node version: 10.10.0
• npm (or yarn) version: 6.0.0

Relevant code or config

npm run precommit

Problem description:

I'm working on a fork of kcd-scripts for my own company's purposes and while testing the lintstagedrc.js file failes on Windows. Probably has to do with #8 or is very similar. I also noticed this when working on React-Testing-Library when I went to commit, again lintstagedrc.js fails.

Unfortunately I'm not versed enough in the fs and path operators to figure out how to change \ for /. Unless we write a dirty method to check for win32 and do a global replace on the path string, tranding slashes. But I don't know what other problems might arise from that.