v4: implement onCancel callbacks (#2022) #2268

Job	Run time
typecheck / typecheck	4m 49s
units / 🧪 Unit Tests	13m 30s
publish-worker-v4 / build (supervisor)	1m 35s
publish-webapp / publish	2m 46s
publish-worker / build (coordinator)	2m 0s
publish-worker / build (docker-provider)	54s
publish-worker / build (kubernetes-provider)	44s
	26m 18s

Provide feedback