[gimp] plug-ins: fix parameters of Gimp.file_save().

[Jehan <jehanp src gnome org>]

commit c86d909dda851d0a8e61808e9c9c63d5c8c6fb23
Author: Jehan <jehan girinstud io>
Date:   Fri Oct 23 15:20:21 2020 +0200

    plug-ins: fix parameters of Gimp.file_save().
    
    It now requires a list of drawables (even though still mostly useless,
    but this comes with the change of multi-selected layers).

 plug-ins/python/py-slice.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/plug-ins/python/py-slice.py b/plug-ins/python/py-slice.py
index 01df236a5a..7bc5dc65c0 100755
--- a/plug-ins/python/py-slice.py
+++ b/plug-ins/python/py-slice.py
@@ -196,7 +196,7 @@ def slice(image, drawable, image_path, image_basename, image_extension,
     if image_extension == "jpg" and image.base_type() == Gimp.ImageBaseType.INDEXED:
         temp_image.convert_rgb ()
 
-    Gimp.file_save(Gimp.RunMode.NONINTERACTIVE, temp_image, temp_drawable,
+    Gimp.file_save(Gimp.RunMode.NONINTERACTIVE, temp_image, [temp_drawable],
                    Gio.file_new_for_path (filename))
 
     temp_image.delete()