bug-fix (by using Qt 6.7.3) qt6...metatypes.json: illegal value (windows nmake)

[pestophagous]

This change shows that the "metatypes.json: illegal value" build error can be avoided by upgrading from Qt 6.5.3 to 6.7.3.

See PR #120 for a bit more discussion (and an alternative workaround).

Whereas the build for the prior PR fails, on this PR the log arrives at completion:

qrc_appReproducejsonbug_raw_qml_0.cpp
[ 95%] Linking CXX executable appReproducejsonbug.exe
	"C:\Program Files\CMake\bin\cmake.exe" -E vs_link_exe --msvc-ver=1929 --intdir=CMakeFiles\appReproducejsonbug.dir --rc=C:\PROGRA~2\WI3CF2~1\10\bin\100226~1.0\x64\rc.exe --mt=C:\PROGRA~2\WI3CF2~1\10\bin\100226~1.0\x64\mt.exe --manifests -- C:\PROGRA~2\MICROS~2\2019\ENTERP~1\VC\Tools\MSVC\1429~1.301\bin\Hostx64\x64\link.exe  @CMakeFiles\appReproducejsonbug.dir\objects1.rsp @C:\Users\RUNNER~1\AppData\Local\Temp\nmEC0F.tmp
[100%] Built target appReproducejsonbug
	"C:\Program Files\CMake\bin\cmake.exe" -E cmake_progress_start D:\a\qt-qml-project-template-with-ci\qt-qml-project-template-with-ci\cbuild\CMakeFiles 0
/d/a/qt-qml-project-template-with-ci/qt-qml-project-template-with-ci
We assume this was run with 'set -e' (look at upper lines of this script).
Assuming so, then getting here means:
win_ci.sh SUCCESS

Log can be found here until it expires: https://github.com/219-design/qt-qml-project-template-with-ci/actions/runs/14743492206

[pestophagous]

Closing. This was always simply for testing and never intended to merge.