[gtk+] build: Install gtkcenterbox.h

[Timm Bäder <baedert src gnome org>]

commit c1082ca93e1aec47acb8bcb0209ca953e9c6064b
Author: Timm Bäder <mail baedert org>
Date:   Tue Aug 15 21:19:48 2017 +0200

    build: Install gtkcenterbox.h

 gtk/meson.build |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/gtk/meson.build b/gtk/meson.build
index 8b8b7a6..a5985a3 100644
--- a/gtk/meson.build
+++ b/gtk/meson.build
@@ -396,6 +396,7 @@ gtk_public_headers = files([
   'gtkbuilder.h',
   'gtkbutton.h',
   'gtkcalendar.h',
+  'gtkcenterbox.h',
   'gtkcellarea.h',
   'gtkcellareabox.h',
   'gtkcellareacontext.h',