doc: add JungMinu to collaborators

PR-URL: https://github.com/nodejs/node/pull/4143
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>
Reviewed-By: Colin Ihrig <http://www.cjihrig.com>
Reviewed-By: Kat Marchán <kzm@sykosomatic.org>
Reviewed-By: James M Snell <jasnell@gmail.com>

README.md

@@ -394,6 +394,7 @@ information about the governance of the Node.js project, see
 * [jbergstroem](https://github.com/jbergstroem) - **Johan Bergström** <bugs@bergstroem.nu>
 * [joaocgreis](https://github.com/joaocgreis) - **João Reis** <reis@janeasystems.com>
 * [julianduque](https://github.com/julianduque) - **Julian Duque** <julianduquej@gmail.com>
+* [JungMinu](https://github.com/JungMinu) - **Minwoo Jung** <jmwsoft@gmail.com>
 * [lxe](https://github.com/lxe) - **Aleksey Smolenchuk** <lxe@lxe.co>
 * [mhdawson](https://github.com/mhdawson) - **Michael Dawson** <michael_dawson@ca.ibm.com>
 * [micnic](https://github.com/micnic) - **Nicu Micleușanu** <micnic90@gmail.com>