bump also controller-gen

Author: jotak

Makefile

@@ -205,7 +205,7 @@ $(CONVERSION_GEN): ## Build conversion-gen from tools folder.
 
 CONTROLLER_GEN = $(shell pwd)/bin/controller-gen
 controller-gen: ## Download controller-gen locally if necessary.
-	$(call go-install-tool,$(CONTROLLER_GEN),sigs.k8s.io/controller-tools/cmd/controller-gen@v0.16.2)
+	$(call go-install-tool,$(CONTROLLER_GEN),sigs.k8s.io/controller-tools/cmd/controller-gen@v0.20.0)
 
 KUSTOMIZE = $(shell pwd)/bin/kustomize
 kustomize: ## Download kustomize locally if necessary.