[gtk+] Update README.in for the GtkIconInfo type change

[Alexander Larsson <alexl src gnome org>]

commit b8af079258944a483785223c3031d2889aaf6bb5
Author: Alexander Larsson <alexl redhat com>
Date:   Thu Feb 14 22:52:49 2013 +0100

    Update README.in for the GtkIconInfo type change

 README.in |    8 ++++++++
 1 files changed, 8 insertions(+), 0 deletions(-)
---
diff --git a/README.in b/README.in
index b5d9f30..120b265 100644
--- a/README.in
+++ b/README.in
@@ -71,6 +71,14 @@ and attach the patch to that bug report.
 
 Patches should be in unified diff form. (The -up option to GNU diff.)
 
+Release notes for 3.6
+=====================
+
+* GtkIconInfo has changed from being a boxed type to a GObject. This
+  is technically an ABI change, but basically all existing code
+  will keep working if its used as a boxed type, and its not
+  possible to instantiate GtkIconInfos outside Gtk, so this is not
+  expected to be a big problem.
 
 Release notes for 3.6
 =====================