debian-cd: fix dead link

Author: RTXUX

debian-cd/prepare.sh

@@ -2,7 +2,7 @@
 set -e
 apk add --no-cache wget ca-certificates rsync
 mkdir -p /etc/jigdo
-wget 'http://atterer.org/sites/atterer/files/2009-08/jigdo/jigdo-bin-0.7.3.tar.bz2'
+wget 'https://ftp.lug.ustc.edu.cn/misc/jigdo-bin-0.7.3.tar.bz2'
 tar xf jigdo-bin-0.7.3.tar.bz2 jigdo-bin-0.7.3/jigdo-file
 mv jigdo-bin-0.7.3/jigdo-file /usr/local/bin/
 rm -rf jigdo-bin-*