eslint used by bulk-decaffeinate fails when run in git bash on Windows

[alangpierce]

Follow-up from #132. For some reason, eslint gives an error even though it works when manually run afterward. I suspect it might be some issue with the filesystem not being updated immediately, but the immediate issue is that bulk-decaffeinate doesn't say what the eslint error was (related to #128).

[jcreek]

I am also experiencing this issue.