data_dir/scylla.yaml: Update to the latest 0.18 Scylla AMIs
data_dir/scylla.yaml: Update to the latest 0.18 Scylla AMIs

Signed-off-by: Lucas Meneghel <8ad3460456640ab580599f5440c5a8d925a620b9@localhost.localdomain>

scylladb/scylla-longevity-tests,amoskong/scylla-cluster-tests,scylladb/scylla-cluster-tests,amoskong/scylla-cluster-tests,scylladb/scylla-longevity-tests,amoskong/scylla-cluster-tests,amoskong/scylla-cluster-tests,scylladb/scylla-cluster-tests,scylladb/scylla-longevity-tests,scylladb/scylla-cluster-tests,scylladb/scylla-cluster-tests,scylladb/scylla-cluster-tests,amoskong/scylla-cluster-tests