[gspell] news: add warning about 1.3.x being unstable releases

[Sébastien Wilmet <swilmet src gnome org>]

commit 4651b689db94bf610ee746856f51052a90debddf
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Sun Dec 11 16:52:36 2016 +0100

    news: add warning about 1.3.x being unstable releases
    
    Forgot it for 1.3.1, it'll be for 1.3.2.

 NEWS |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/NEWS b/NEWS
index c382e7e..1ec5db9 100644
--- a/NEWS
+++ b/NEWS
@@ -1,5 +1,8 @@
 News in 1.3.1
 -------------
+This is an unstable release in the 1.3 development cycle. The 1.4 stable
+version will be released at the same time as GNOME 3.24.
+
 * Add inline spell-checking support for GtkEntry (the bases are there).
 * GtkTextView support: fix populate-popup signal param type
 * Translation updates