[gtkmm] Fix typo

[Murray Cumming <murrayc src gnome org>]

commit 4f5a4bc8644d6fee431e9d81c65458053fed3683
Author: Murray Cumming <murrayc murrayc com>
Date:   Wed Apr 6 16:24:10 2011 +0200

    Fix typo

 NEWS |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/NEWS b/NEWS
index 979b699..bc2fe2a 100644
--- a/NEWS
+++ b/NEWS
@@ -52,7 +52,7 @@ General:
 See also the list of new API in gtkmm 3.0:
 http://developer.gnome.org/gtkmm/unstable/since_3_0.html
 
-3.0.0 (unstable):
+3.0.0 (stable):
 
 Gtk:
 * Change all operator void* to operator const void*, with a BoolExpr typedef