electron-builder already bundles @malept/flatpak-bundler, so this just
adds the target + a finishArgs set matching the app's actual needs:
wayland/x11 rendering, PipeWire for WebRTC screen/mic capture (on top
of the base pulseaudio socket), camera device access, and the
freedesktop notifications + portal bus names (native/linux-portals
handles file chooser/background/global-shortcuts through the latter).
Bumped runtime/base to 23.08 from electron-builder's very old 20.08
default.
Building this target requires flatpak + flatpak-builder installed on
the build machine (Linux-only, can't run on macOS at all), plus the
org.freedesktop.Platform/Sdk and org.electronjs.Electron2.BaseApp
23.08 runtimes from Flathub.
brenden
6b2e9ec669