F34 update workarounds: drop systemd, add jpegxl

This systemd update went stable ages ago. But now we need to add
a jpegxl update as a workaround to avoid KDE live build tests
failing on the problematic aom->jpegxl-libs->gimp dependency
chain I identified yesterday. It makes KDE live builds pull in
too many packages and fail because they run out of space.

Signed-off-by: Adam Williamson <awilliam@redhat.com>

lib/utils.pm

@@ -445,7 +445,7 @@ sub setup_workaround_repo {
     my %workarounds = (
         "32" => [],
         "33" => [],
-        "34" => ["FEDORA-2021-c2bfa5e4f6"]
+        "34" => ["FEDORA-2021-d7b1dc57fe"]
     );
     # then we'll download each update for our release:
     my $advortasks = $workarounds{$version};