In theory we support Qt 5.6 (because of SailfishOS) but in practice we are not checking that in the CI so probably we broke the compatibility long ago. Also, I don't think anyone is using this code in SailfishOS, so we can greatly simplify the code by requiring Qt 5.15 or later.
The moc process already rebuilds the plugin when the JSON file changes, consequently the additional parameter is not needed.
Task: https://phabricator.kde.org/T14649
Without it, the build may fail with:
fatal error: kcmutils_version.h: No such file or directory
35 | #include <kcmutils_version.h>
| ^~~~~~~~~~~~~~~~~~~~
This automatizes the generation of logging categories so a
kdeconnect-kde.categories is generated and installed to
/usr/share/qlogging-categories5/ so kdebugsettings can use it.
Also, sets the default logging level to Warning. So now the logs
of users won't be filled with debug messages but they can
modify the configuration easily with kdebugsettings.
