__package_apt: fix complain about suite change

the last fix for ticket #861 :-)

cdist/conf/type/__package_apt/gencode-remote

@@ -81,12 +81,24 @@ aptget="DEBIAN_FRONTEND=noninteractive apt-get --quiet --yes -o Dpkg::Options::=
 
 case "$state_should" in
     present)
+        # There are special arguments to apt(8) to prevent aborts if apt woudn't been
+        # updated after the 19th April 2021 till the bullseye release. The additional
+        # arguments acknoledge the happend suite change (the apt(8) update does the
+        # same by itself).
+        #
+        # Using '-o $config' instead of the --allow-releaseinfo-change-* parameter
+        # allows backward compatablility to pre-buster Debian versions.
+        #
+        # See more: ticket #861
+        # https://code.ungleich.ch/ungleich-public/cdist/-/issues/861
+        apt_opts="-o Acquire::AllowReleaseInfoChange::Suite=true -o Acquire::AllowReleaseInfoChange::Version=true"
+
         # following is bit ugly, but important hack.
         # due to how cdist config run works, there isn't
         # currently better way to do it :(
         cat << EOF
 if [ ! -f /var/cache/apt/pkgcache.bin ] || [ "\$( stat --format %Y /var/cache/apt/pkgcache.bin )" -lt "\$( date +%s -d '-1 day' )" ]
-then echo apt-get update > /dev/null 2>&1 || true
+then echo apt-get $apt_opts update > /dev/null 2>&1 || true
 fi
 EOF
         if [ -n "$version" ]; then