compile failure in umbrello master

[Jonathan Riddell]

https://build.neon.kde.org/job/bionic_unstable_kde_umbrello_bin_amd64/43/console

from /workspace/build/umbrello/main.cpp:12:
17:21:13 /usr/include/KF5/KCoreAddons/kaboutdata.h:1173:1: error:
specialization of ‘template<class T> struct QMetaTypeId’ in different
namespace [-fpermissive]
17:21:13  Q_DECLARE_METATYPE(KAboutData)
17:21:13  ^

Jonathan