update AUTHORS.md

Author: feross

AUTHORS.md

@@ -27,5 +27,6 @@
 - Diego Rodríguez Baquero <DiegoRBaquero@users.noreply.github.com>
 - Autarc <autarc@gmail.com>
 - Kirill Fomichev <fanatid@ya.ru>
+- Matt Bell <mappum@gmail.com>
 
 #### Generated by bin/update-authors.sh.