Add listchanges.conf template for Debian sid.

diff --git a/templates/Debian/listchanges_sid.erb b/templates/Debian/listchanges_sid.erb
new file mode 120000 (symlink)
index 0000000..74ab496
--- /dev/null
+++ b/templates/Debian/listchanges_sid.erb
@@ -0,0 +1 @@
+listchanges_lenny.erb
\ No newline at end of file