drop use of code-generator/generate-groups.sh #2505

Job	Run time
Unit Test (knative/serving)	10m 33s
Unit Test (knative/networking)	4m 58s
Unit Test (knative/eventing)	13m 4s
Unit Test (knative/operator)	6m 58s
Unit Test (knative/client)	7m 28s
Unit Test (knative-extensions/eventing-autoscaler-keda)	5m 22s
Unit Test (knative-extensions/eventing-ceph)	5m 17s
Unit Test (knative-extensions/eventing-github)	5m 49s
Unit Test (knative-extensions/eventing-gitlab)	6m 2s
Unit Test (knative-extensions/eventing-kafka-broker)	10m 29s
Unit Test (knative-extensions/eventing-rabbitmq)	8m 31s
Unit Test (knative-extensions/eventing-redis)	6m 12s
Unit Test (knative-extensions/kn-plugin-admin)	5m 27s
Unit Test (knative-extensions/net-certmanager)	4m 59s
Unit Test (knative-extensions/net-contour)	5m 5s
Unit Test (knative-extensions/net-istio)	5m 43s
Unit Test (knative-extensions/net-kourier)	5m 13s
	1h 57m 10s

Provide feedback