[gnome-panel] bump version to 3.28.0, update NEWS

[Alberts Muktupāvels <muktupavels src gnome org>]

commit adbeb24ddd152c1e5ef481e7d24b0a74c6c4b3dd
Author: Alberts Muktupāvels <alberts muktupavels gmail com>
Date:   Sun Mar 25 15:56:36 2018 +0300

    bump version to 3.28.0, update NEWS

 NEWS         |   11 +++++++++++
 configure.ac |    2 +-
 2 files changed, 12 insertions(+), 1 deletions(-)
---
diff --git a/NEWS b/NEWS
index 644c965..0bf4fb4 100644
--- a/NEWS
+++ b/NEWS
@@ -1,3 +1,14 @@
+Version 3.28.0
+==============
+- Turn old menu bar object into applet
+- Fix some build warnings
+- Updated translations:
+  Anders Jonsson (sv), Ask Hjorth Larsen (da), Daniel Mustieles (es),
+  Dingzhong Chen (zh_CN), Gábor Kelemen (hu), Kukuh Syafaat (id),
+  Marek Cernocky (cs), Mario Blättermann (de), Matej Urbančič (sl),
+  Мирослав Николић (sr, sr@latin), Piotr Drąg (pl), Rafael Fontenelle (pt_BR),
+  Sveinn í Felli (is).
+
 Version 3.26.0
 ==============
 - Fix custom background color. (#783168)
diff --git a/configure.ac b/configure.ac
index 1284a58..885a58a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -3,7 +3,7 @@ dnl Define version info
 dnl **************************************************************************
 
 m4_define([gp_major_version], [3])
-m4_define([gp_minor_version], [26])
+m4_define([gp_minor_version], [28])
 m4_define([gp_micro_version], [0])
 m4_define([gp_version], [gp_major_version.gp_minor_version.gp_micro_version])