Updated tk-maya to v0.9.9

Updated Maya version to support 2020

Author: mathurf

env/includes/common/engines.yml

@@ -27,7 +27,7 @@ common.engines.tk-houdini.location:
 common.engines.tk-maya.location:
   type: app_store
   name: tk-maya
-  version: v0.9.8
+  version: v0.9.9
 
 # Nuke
 common.engines.tk-nuke.location: