Set distrib to UNRELEASED and document last changes.

debian/changelog

-xtpcpp (0.4.9-2) unstable; urgency=low
+xtpcpp (0.4.9-2) UNRELEASED; urgency=low
 
   * Changed the maintainer to debichem team as the code is now
     in https://salsa.debian.org/debichem-team/xtpcpp.
 
+  * Add Thomas Renne as Copyright holder for GPL3+ code in 2019,2020.
+
   * Add the corresponding VCS fields (see above).
 
-  * NO other changes whatsoever with respect to version -1.
 
  -- Filippo Rusconi <lopippo@debian.org>  Mon, 09 Nov 2020 20:55:49 +0100