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

[Alberts Muktupāvels <muktupavels src gnome org>]

commit 909affb5735b95869ac4580f55b8206c3323f3d7
Author: Alberts Muktupāvels <alberts muktupavels gmail com>
Date:   Sun Mar 25 17:02:45 2018 +0300

    bump version to 3.28.0, update NEWS

 NEWS         |   10 ++++++++++
 configure.ac |    2 +-
 2 files changed, 11 insertions(+), 1 deletions(-)
---
diff --git a/NEWS b/NEWS
index 5d2de08..26118db 100644
--- a/NEWS
+++ b/NEWS
@@ -1,3 +1,13 @@
+Version 3.28.0
+==============
+- Use symbolic window close icon. (#794234)
+- Remove nautilus-classic from required components.
+- Remove A11yKeyboard plugin from required components.
+- Updated translations:
+  Ask Hjorth Larsen (da), Balázs Meskó (hu), Daniel Mustieles (es),
+  Dingzhong Chen (zh_CN), Isaac F. Ferreira Filho (pt_BR), Joe Hansen (da),
+  Мирослав Николић (sr, sr@latin).
+
 Version 3.26.0
 ==============
 - Don't include selection overlay in screenshot. (#780358)
diff --git a/configure.ac b/configure.ac
index d493434..446514e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -3,7 +3,7 @@ dnl Define version info
 dnl **************************************************************************
 
 m4_define([gf_major_version], [3])
-m4_define([gf_minor_version], [26])
+m4_define([gf_minor_version], [28])
 m4_define([gf_micro_version], [0])
 m4_define([gf_version], [gf_major_version.gf_minor_version.gf_micro_version])