Bug#904556: libgtk2-trayicon-perl: Don't ship libgtk2-trayicon-perl in Buster

[intrigeri at debian.org]

Package: libgtk2-trayicon-perl
Version: 0.06-2
Severity: serious

GTK+ 2 has been deprecated upstream for years. Let's ship as little
Perl GTK+ 2 bindings as we can in Buster.

This package has only one reverse-dependency in the archive
(checkgmail), which is orphaned and dead upstream. I'll file a bug
against checkgmail itself to explain the situation to anyone
interested there.