[QGIS-Developer] Updating osgeo4w to qt 5.12.4/5.13.1

[Nyall Dawson]

Hi Jürgen,

Is there any plans on the horizon for updating the Qt build in
osgeo4w? I ask because of these issues (all relate to crashes when
exporting hi resolution layouts):

> - https://github.com/qgis/QGIS/issues/31100
> https://github.com/qgis/QGIS/issues/29065 and
> https://github.com/qgis/QGIS/issues/29768
> https://github.com/qgis/QGIS/issues/29064
> https://github.com/qgis/QGIS/issues/29065

These have a confirmed fix in qt 5.12.4 and 5.13.1 (I've verified):

See bugreports.qt.io/browse/QTBUG-75082 and https://codereview.qt-project.org/c/
qt/qtbase/+/258696)

Kind regards,
Nyall