[Pkg-xmpp-devel] Unify maintainer address

[W. Martin Borgert]

Hi,

currently, 36 packages use pkg-xmpp-devel at lists.alioth.debian.org,
while 5 use pkg-xmpp-devel at alioth-lists.debian.net. According to
https://lists.debian.org/debian-devel/2018/10/msg00004.html it is
better to keep the former address.

I suggest to change it in prosody, prosody-modules, psi-plus,
psi-plus-l10n, and qxmpp, on occasion.

Cheers