CI: Fix Ubuntu 2004 config files

Also, update to the latest packer image

Change-Id: I3fe4a9a954d74b68a31364cfe555f5c7e33baef9
Signed-off-by: Jessica Wagantall <jwagantall@linuxfoundation.org>
diff --git a/jenkins-config/clouds/openstack/cattle/ubuntu2004-builder-2c-2g.cfg b/jenkins-config/clouds/openstack/cattle/ubuntu2004-builder-2c-2g.cfg
index 8a6a635..fcf6ea6 100644
--- a/jenkins-config/clouds/openstack/cattle/ubuntu2004-builder-2c-2g.cfg
+++ b/jenkins-config/clouds/openstack/cattle/ubuntu2004-builder-2c-2g.cfg
@@ -1,4 +1,4 @@
-LABELS=ubuntu1804-builder-2c-2g
-IMAGE_NAME=ZZCI - Ubuntu 18.04 - builder - x86_64 - 20220920-114402.749
+LABELS=ubuntu2004-builder-2c-2g
+IMAGE_NAME=ZZCI - Ubuntu 20.04 - builder - x86_64 - 20240101-020156.263
 HARDWARE_ID=v2-highcpu-2
 VOLUME_SIZE=20