Makefile: fix setup-envtest to latest version supporting 1.21

Author: Felix Wischke (65278)

Makefile

@@ -203,7 +203,7 @@ $(CONTROLLER_GEN): $(LOCALBIN)
 .PHONY: envtest
 envtest: $(ENVTEST) ## Download envtest-setup locally if necessary.
 $(ENVTEST): $(LOCALBIN)
-	test -s $(LOCALBIN)/setup-envtest || GOBIN=$(LOCALBIN) go install sigs.k8s.io/controller-runtime/tools/setup-envtest@latest
+	test -s $(LOCALBIN)/setup-envtest || GOBIN=$(LOCALBIN) go install sigs.k8s.io/controller-runtime/tools/setup-envtest@v0.0.0-20240208111015-5923139bc5bd
 
 ##@ Test