Merge pull request #606 from SmartThingsCommunity/fix/sonos-group-volume-setgroupvolume-wrong-payload-key

Author: dljsjr

drivers/SmartThings/sonos/src/api/cmd_handlers.lua

@@ -140,7 +140,7 @@ function CapCommandHandlers.handle_group_volume_down(driver, device, cmd)
 end
 
 function CapCommandHandlers.handle_group_set_volume(driver, device, cmd)
-  local new_volume = st_utils.clamp_value(cmd.args.volume, 0, 100)
+  local new_volume = st_utils.clamp_value(cmd.args.groupVolume, 0, 100)
   local payload = {
     { namespace = "groupVolume", command = "setVolume" },
     { volume = new_volume }