wxWidgets 3.2 provides a Qt frontend in addition to the GTK3 one, so packages have been renamed from wxgtk-* to wxwidgets-*. The GTK2 frontend is no longer provided. If you have wxgtk2 installed, the upgrade will fail with

error: failed to prepare transaction (could not satisfy dependencies) :: removing wxgtk-common breaks dependency 'wxgtk-common' required by wxgtk2

In such case, uninstall wxgtk2 first with

# pacman -Rc wxgtk2

and then proceed with the upgrade.