[gnome-todo] Drop use of GtkBox pack API

[Emmanuele Bassi <ebassi src gnome org>]

commit 0d4c0449170bbea59a0082efcfe040c3ba5ef28a
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Sun Jan 27 15:07:04 2019 +0000

    Drop use of GtkBox pack API
    
    The pack API was removed from GtkBox in GTK 4.

 src/gtd-window.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)
---
diff --git a/src/gtd-window.c b/src/gtd-window.c
index f8c2688..4b38d7a 100644
--- a/src/gtd-window.c
+++ b/src/gtd-window.c
@@ -135,7 +135,7 @@ add_widgets (GtdWindow *self,
       switch (gtk_widget_get_halign (l->data))
         {
         case GTK_ALIGN_START:
-          gtk_box_pack_start (GTK_BOX (container_start), l->data);
+          gtk_container_add (GTK_CONTAINER (container_start), l->data);
           break;
 
         case GTK_ALIGN_CENTER:
@@ -143,13 +143,13 @@ add_widgets (GtdWindow *self,
           break;
 
         case GTK_ALIGN_END:
-          gtk_box_pack_end (GTK_BOX (container_end), l->data);
+          gtk_container_add (GTK_CONTAINER (container_end), l->data);
           break;
 
         case GTK_ALIGN_BASELINE:
         case GTK_ALIGN_FILL:
         default:
-          gtk_box_pack_start (GTK_BOX (container_start), l->data);
+          gtk_container_add (GTK_CONTAINER (container_start), l->data);
           break;
         }
     }