Previously, `yarn prettier` didn't write changed files since `glob` produced paths relative to cwd and `git diff --name-only` produced paths relative to git root directory. This changes `git diff --name-only` to `git diff --name-only --relative`
Copies over the prettier script from the React repo with a few tiny tweaks for a nicer experience running prettier on changed files
Joe Savona
Mofei Zhang
mofeiZ
Lauren Tan