[gimp] plug-ins: fix goat-exercise-lua not working after the split between Gimp and GimpUi.

[Jehan <jehanp src gnome org>]

commit da9284b737d7cdb11502e5d8a1f7a882030c9ec0
Author: Jacob Boerema <jgboerema gmail com>
Date:   Thu Jul 30 13:57:53 2020 -0400

    plug-ins: fix goat-exercise-lua not working after the split between Gimp and GimpUi.

 plug-ins/goat-exercises/goat-exercise-lua.lua | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/plug-ins/goat-exercises/goat-exercise-lua.lua b/plug-ins/goat-exercises/goat-exercise-lua.lua
index 91c28611ce..d359e4b78b 100755
--- a/plug-ins/goat-exercises/goat-exercise-lua.lua
+++ b/plug-ins/goat-exercises/goat-exercise-lua.lua
@@ -40,7 +40,7 @@ function run(procedure, run_mode, image, drawable, args, run_data)
   -- Not sure why run_mode has become a string instead of testing
   -- against Gimp.RunMode.INTERACTIVE.
   if run_mode == "INTERACTIVE" then
-    Gimp.ui_init("goat-exercise-lua");
+    GimpUi.ui_init("goat-exercise-lua");
     local dialog = GimpUi.Dialog {
       title          = "Exercise a goat (Lua)",
       role           = "goat-exercise-Lua",