doc: add StefanStojanovic to collaborators

Fixes: nodejs#52929
PR-URL: nodejs#53118
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Reviewed-By: Marco Ippolito <marcoippolito54@gmail.com>

README.md

@@ -433,6 +433,8 @@ For information about the governance of the Node.js project, see
   **Paolo Insogna** <<paolo@cowtech.it>> (he/him)
 * [srl295](https://github.com/srl295) -
   **Steven R Loomis** <<srl295@gmail.com>>
+* [StefanStojanovic](https://github.com/StefanStojanovic) -
+  **Stefan Stojanovic** <<stefan.stojanovic@janeasystems.com>> (he/him)
 * [sxa](https://github.com/sxa) -
   **Stewart X Addison** <<sxa@redhat.com>> (he/him)
 * [targos](https://github.com/targos) -