archrelease: Copy new files from trunk

Currently, files that have just been added to trunk are not copied to
the repositories when invoking archrelease, as `svn ls` does not list
them if we don't `svn update` explicitly before. Use `svn ls -r HEAD` to
include everything from current HEAD. Fixes FS#25680.

Reported-by: Eric Bélanger <snowmaniscool@gmail.com>
Signed-off-by: Lukas Fleischer <archlinux@cryptocrack.de>
Signed-off-by: Pierre Schmitz <pierre@archlinux.de>