doc: add saghul as a collaborator

PR_URL: #3724
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Evan Lucas <evanlucas@me.com>
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>
Reviewed-By: Myles Borins <mborins@us.ibm.com>

Author: saghul

README.md

@@ -367,6 +367,7 @@ information about the governance of the Node.js project, see
 * [qard](https://github.com/qard) - **Stephen Belanger** <admin@stephenbelanger.com>
 * [rlidwka](https://github.com/rlidwka) - **Alex Kocharin** <alex@kocharin.ru>
 * [robertkowalski](https://github.com/robertkowalski) - **Robert Kowalski** <rok@kowalski.gd>
+* [saghul](https://github.com/saghul) - **Saúl Ibarra Corretgé** <saghul@gmail.com>
 * [sam-github](https://github.com/sam-github) - **Sam Roberts** <vieuxtech@gmail.com>
 * [seishun](https://github.com/seishun) - **Nikolai Vavilov** <vvnicholas@gmail.com>
 * [silverwind](https://github.com/silverwind) - **Roman Reiss** <me@silverwind.io>