doc: add AndreasMadsen to collaborators

PR-URL: #5666
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Evan Lucas <evanlucas@me.com>
Reviewed-By: Glen Keane <glenkeane.94@gmail.com>

Author: AndreasMadsen

README.md

@@ -158,6 +158,7 @@ information about the governance of the Node.js project, see
 
 ### Collaborators
 
+* [AndreasMadsen](https://github.com/AndreasMadsen) - **Andreas Madsen** <amwebdk@gmail.com>
 * [benjamingr](https://github.com/benjamingr) - **Benjamin Gruenbaum** <benjamingr@gmail.com>
 * [brendanashworth](https://github.com/brendanashworth) - **Brendan Ashworth** <brendan.ashworth@me.com>
 * [calvinmetcalf](https://github.com/calvinmetcalf) - **Calvin Metcalf** <calvin.metcalf@gmail.com>