build: bump version to 3.9.0
build: bump version to 3.9.0

rgcjonas/adwaita-semidark,rgcjonas/adwaita-semidark,Distrotech/gnome-themes-standard,DoctorJellyface/gnome-themes-standard,rgcjonas/adwaita-semidark,rgcjonas/adwaita-semidark,DoctorJellyface/gnome-themes-standard,Distrotech/gnome-themes-standard