[gnome-latex] News: add news for release 3.28.1

[Sébastien Wilmet <swilmet src gnome org>]

commit 8e2d468f24f7f558cdb115c681c6e6ebef7763d2
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Sun May 20 13:15:32 2018 +0200

    News: add news for release 3.28.1

 NEWS | 12 ++++++++++++
 1 file changed, 12 insertions(+)
---
diff --git a/NEWS b/NEWS
index 32dde85..aadc020 100644
--- a/NEWS
+++ b/NEWS
@@ -1,5 +1,17 @@
 GNOME LaTeX NEWS
 
+Release 3.28.1, 2018-05-20
+--------------------------
+* Warning for packagers:
+  For the Vala code you must keep the generated C code from the tarball,
+  because if the C code is re-generated with valac >= 0.41 then gnome-latex
+  will have various crashes.
+
+* New configure build option: --disable-dconf-migration, intended to be used
+  only on OSes where dconf cannot be installed.
+
+* Translation updates.
+
 Release 3.28.0, 2018-04-08
 --------------------------
 * Changes for packagers: