Log Message:
chat/spectrum: Update python comment

This was marked 27 only because of xmpppy.  xmpppy now works with 3,
but trying to build spectrum fails because of include 2.7-only code.

Spectrum 2.2.0 was released in 2023, and there have been many releases
since 1.4.8 in 2011, so an update is overdue :-(