Add g-i-s timezone bug fix updates as workarounds

This should avoid the bug happening in upgrade tests (I already
built the fix into the base disk image, which should avoid it
happening in other tests).

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

lib/utils.pm

@@ -443,8 +443,9 @@ sub setup_workaround_repo {
     assert_script_run "pushd /opt/workarounds_repo";
     my %workarounds = (
         "30" => [],
-        "31" => [],
-        "32" => []
+        # gnome-initial-setup timezone bug fix
+        "31" => ["FEDORA-2020-da78f28e61"],
+        "32" => ["FEDORA-2020-74b4efe302"]
     );
     # then we'll download each update for our release:
     my $advisories = $workarounds{$version};