cupsd: Add /etc/paperspecs read access

Cups uses libpaper which accesses /etc/paperspecs.

ce42216e2e/lib/libpaper.c.in.in (L419)

profiles/apparmor/profiles/extras/usr.sbin.cupsd

@@ -65,6 +65,8 @@ include <tunables/global>
   /var/cache/cups/ rw,
   /var/cache/cups/** rw,
 
+  /etc/paperspecs r,
+
   # Site-specific additions and overrides. See local/README for details.
   include if exists <local/usr.sbin.cupsd>
 }