'PlugIns' is normal for MacOS and whatever is generating qt.conf
(macdeployqt?) is using 'PlugIns', so this both builds and generates
an app that works on case insensitive filesystems but fails to load
on case sensitive filesystems.
I haven't tested building the installer, only modifying the
qt.conf in the installed copy of OBS.app.
Fixes https://github.com/obsproject/obs-studio/issues/2302
dc17171617
