Add mjmahone to May 2020 WG (#404)

Co-authored-by: Lee Byron <[email protected]>

Author: mjmahone

agendas/2020-05-07.md

@@ -37,6 +37,7 @@ agenda, edit this file.*
 | Stephen Spalding         | Netflix                  | Los Gatos, CA
 | Evan Huus                | Shopify                  | Ottawa, ON, CA
 | Andrew Sprouse           | TakeShape                | Brooklyn, NY
+| Matt Mahoney             | Facebook                 | Brooklyn, NY
 | Morris Matsa             | IBM                      | Boston, US
 | *ADD YOUR NAME ABOVE TO ATTEND*