Add changes file for Qt 5.9.4

Change-Id: I20e1659b47f11733907f836782ac1a717891b35a
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@qt.io>

dist/changes-5.9.4

@@ -0,0 +1,31 @@
+Qt 5.9.4 is a bug-fix release. It maintains both forward and backward
+compatibility (source and binary) with Qt 5.9.0.
+
+For more details, refer to the online documentation included in this
+distribution. The documentation is also available online:
+
+http://doc.qt.io/qt-5/index.html
+
+The Qt version 5.9 series is binary compatible with the 5.8.x series.
+Applications compiled for 5.8 will continue to run with 5.9.
+
+Some of the changes listed in this file include issue tracking numbers
+corresponding to tasks in the Qt Bug Tracker:
+
+https://bugreports.qt.io/
+
+Each of these identifiers can be entered in the bug tracker to obtain more
+information about a particular change.
+
+****************************************************************************
+*                               Qt 5.9.4 Changes                           *
+****************************************************************************
+
+QtBLuetooth
+-----------
+
+ - [QTBUG-64669] Fixed hanging service discovery state when remote device
+   does not respond to ATT read requests.
+ - [QTBUG-64597] Fixed compilation of heartrate server example with disabled
+   gui module.
+ - Added minor improvements to Windows UWP builds.