Update TSC stakeholders

This changelist assigns Fran Gonzalez as the Pixar RenderMan stakeholder on the MaterialX TSC, and adds Bernard Kwok as the Khronos Group stakeholder, as confirmed by votes at recent meetings.

Author: jstone-lucasfilm

GOVERNANCE.md

@@ -63,10 +63,11 @@ MaterialX project, though they are encouraged to do so.
 The current Stakeholders of the MaterialX TSC are:
 
 - Eric Bourque - Autodesk
+- Fran Gonzalez - Pixar RenderMan
 - Rafal Jaroszkiewicz - SideFX
 - Lee Kerley - Sony Pictures Imageworks
 - Lutz Kettner - NVIDIA
-- Philippe Leprince - Pixar RenderMan
+- Bernard Kwok - Khronos Group
 - Jonathan Litt - Epic Games
 - André Mazzone - ILM
 - Magnus Pettersson - IKEA