Make tar'ing the examples code non-verbose

No point seeing this every time we build a repo:

/usr/bin/tar: Option --mtime: Treating date '@1661860812' as 2022-08-30 14:00:12
./
./CMakeLists.txt
./LICENSES/
./LICENSES/LGPL-2.1-or-later.txt
./Messages.sh
./README.md
./install.sh
./ioworker.kdevtemplate
./src/
./src/%{APPNAMELC}.cpp
./src/%{APPNAMELC}.h
./src/CMakeLists.txt
./src/mydatasystem.cpp
./src/mydatasystem.h
./src/myproto.json
./uninstall.sh

To debug something with it, we can temporarily put the -v option back.