Add Matt Farmer to 2020-02-06.md agenda

I've been working on the [implementation](graphql/graphql-js#2276) of the `@specified(by: "")` directive as specified by graphql/graphql-spec#649, and am interested an any feedback or progress on that effort.

Author: m14t

agendas/2020-02-06.md

@@ -25,6 +25,7 @@ agenda, edit this file.*
 | Name                     | Organization / Project   | Location
 | ------------------------ | ------------------------ | ------------------------
 | Lee Byron                | GraphQL Foundation       | San Francisco, CA, US
+| Matt Farmer              | Individual Contrib       | Oakland, CA, US
 | *ADD YOUR NAME ABOVE TO ATTEND*