Add changes file for Qt 5.12.1

+ 4d57f6bc47 QtQuick: Fix & clean up alarms.pro
+ 113e24a5aa Doc: Add brief section to "Qt for QNX", "Qt for VxWorks"
+ ec6883bd7c Doc: Remove broken link from iOS documentation
+ 9c8b608839 Bump version
+ 9aec0395d2 Make example code in Qt documentation also available under BSD-3-clause
+ b6a5aff9b7 Improve the exception safety code sample
+ 144395f0aa Fix the usage of the ret variable in the exception safety code sample
+ 66bddfb570 Add changes file for Qt 5.11.3
+ 4db2e07f97 Doc: Document Qt Quick WebGL plugin license
+ a58fa967f2 Doc: Remove obsolete build instructions for Qt Quick WebGL plugin
+ 0a47462880 winrt: Update winrtrunner's help output
+ 8f7c4db0ad Clarify target platforms of winrt port
+ c162c4b5a5 windows: Fix origin of environment setup script
+ 9d88932795 Doc: Replace Controls 1 and MouseArea references
+ 3361d00443 Doc: Change the depends order in the doc config
+ ec479952c0 remove references to bundled xkbcommon
+ 10b3f2c109 macOS: improve quit menu item documentation
+ bfe5411391 Bump version

Change-Id: I63e1c88a718757a55904c5a0f4358aa651e5a40c
Reviewed-by: Topi Reiniö <topi.reinio@qt.io>

dist/changes-5.12.1

@@ -0,0 +1,12 @@
+Qt 5.12.1 is a bug-fix release. It maintains both forward and backward
+compatibility (source and binary) with Qt 5.12.0.
+
+For more details, refer to the documentation included in this
+distribution. The documentation is also available online:
+
+https://doc.qt.io/qt-5/
+
+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.
+
+ - This release contains only minor code improvements.