meta: fix collaborator list errors in README.md

Add missing `-` characters in the list.

PR-URL: #31655
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Yuta Hiroto <hello@hiroppy.me>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

Author: jasnell

README.md

@@ -353,7 +353,7 @@ For information about the governance of the Node.js project, see
 **Denys Otrishko** <shishugi@gmail.com> (he/him)
 * [maclover7](https://github.com/maclover7) -
 **Jon Moss** <me@jonathanmoss.me> (he/him)
-* [mafintosh](https://github.com/mafintosh)
+* [mafintosh](https://github.com/mafintosh) -
 **Mathias Buus** <mathiasbuus@gmail.com> (he/him)
 * [mcollina](https://github.com/mcollina) -
 **Matteo Collina** <matteo.collina@gmail.com> (he/him)
@@ -385,7 +385,7 @@ For information about the governance of the Node.js project, see
 **Refael Ackermann (רפאל פלחי)** <refack@gmail.com> (he/him/הוא/אתה)
 * [richardlau](https://github.com/richardlau) -
 **Richard Lau** <riclau@uk.ibm.com>
-* [ronag](https://github.com/ronag)
+* [ronag](https://github.com/ronag) -
 **Robert Nagy** <ronagy@icloud.com>
 * [ronkorving](https://github.com/ronkorving) -
 **Ron Korving** <ron@ronkorving.nl>