Add changes file for Qt 5.12.4

Change-Id: I6f3f2b3c3a231ac661c0f5e9d5feeb6f7e09f2de
Reviewed-by: Liang Qi <liang.qi@qt.io>

dist/changes-5.12.4

@@ -0,0 +1,28 @@
+Qt 5.12.4 is a bug-fix release. It maintains both forward and backward
+compatibility (source and binary) with Qt 5.12.0 through 5.12.3.
+
+For more details, refer to the online documentation included in this
+distribution. The documentation is also available online:
+
+https://doc.qt.io/qt-5/index.html
+
+The Qt version 5.12 series is binary compatible with the 5.11.x series.
+Applications compiled for 5.11 will continue to run with 5.12.
+
+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.
+
+****************************************************************************
+*                                 General                                  *
+****************************************************************************
+
+ - The qtimageformats module now offers configuration settings
+   available in the global Qt configure. The image format handlers
+   based on external codecs can be enabled or disabled, and the choice
+   between bundled and system codec library can be set.
+