[gtksourceview] subprojects: specify direct dependency for GTK

[Christian Hergert <chergert src gnome org>]

commit 35c18cd2d8b5202c2960314d9f3ef10d713b5df9
Author: Christian Hergert <chergert redhat com>
Date:   Wed Feb 2 13:27:00 2022 -0800

    subprojects: specify direct dependency for GTK

 subprojects/gtk.wrap | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/subprojects/gtk.wrap b/subprojects/gtk.wrap
index 2a6f74fe..d56b1c10 100644
--- a/subprojects/gtk.wrap
+++ b/subprojects/gtk.wrap
@@ -6,4 +6,5 @@ revision=main
 depth=1
 
 [provide]
+gtk4 = libgtk_dep
 dependency_names=gtk4