Add @mjmahone to 06-wg-primary.md (#1682)

Author: mjmahone

agendas/2025/03-Mar/06-wg-primary.md

@@ -115,6 +115,7 @@ hold additional secondary meetings later in the month.
 | Pascal Senn      | @pascalsenn   | ChilliCream        | Zurich, CH            |
 | Michael Staib    | @michaelstaib | ChilliCream        | Zurich, CH            |
 | Janette Cheng    | @janettec     | Meta               | New York, NY, US      |
+| Matt Mahoney     | @mjmahone     | Meta               | New York, NY, US      |
 
 ## Agenda