Release of patched version with Node 10 engines field

[bcoe]

Hello @touv 👋

I recently enabled --engines-strict on builds, and I noticed that version 4.x of csv-string requires Node 12.

We've been making an effort to follow the Node release schedule, and this stops us from being able to use your module.

I was wondering if there's any chance you might consider back porting recent security fixes to a 3.x release, or alternatively, reconsidering the Node 12 engines requirement?