exo: Update version from 0.12.2 to 0.12.3

> Release notes for 0.12.3
> ========================
> General:
> - Preferred Applications: Improved layout spacing and alignment
> - Resolved g_type_class_add_private deprecations (GObject 2.58)
>
> Bug Fixes:
> - Hide exo launchers from GNOME Software (Xfce #14588)
> - Fix crash with "preedit-changed" signal (Xfce #14756)

exo.be0

@@ -1,6 +1,6 @@
 #!/usr/bin/env beesh
 
-# BEE_VERSION exo-0.12.2-0
+# BEE_VERSION exo-0.12.3-0
 
 SRCURL[0]="http://archive.xfce.org/src/xfce/exo/${PKGVERSION[2]}/exo-${PKGVERSION}.tar.bz2"