chore: pin setup-envtest version

kubernetes-sigs/controller-runtime#2693 broke
the content provider while doing docker-build with following issue[1]

In order to unblock the CI, we are pinning
sigs.k8s.io/controller-runtime/tools/setup-envtest at previous working
commit[2]

[1]. kubernetes-sigs/controller-runtime#2720
[2]. kubernetes-sigs/controller-runtime@c7e1dc9

Signed-off-by: Hongwei Liu <hongliu@redhat.com>

Makefile

@@ -183,7 +183,7 @@ $(CONTROLLER_GEN): $(LOCALBIN)
 .PHONY: envtest
 envtest: $(ENVTEST) ## Download envtest-setup locally if necessary.
 $(ENVTEST): $(LOCALBIN)
-	GOBIN=$(LOCALBIN) go install sigs.k8s.io/controller-runtime/tools/setup-envtest@latest
+	GOBIN=$(LOCALBIN) go install sigs.k8s.io/controller-runtime/tools/setup-envtest@c7e1dc9b
 
 .PHONY: bundle
 bundle: manifests kustomize ## Generate bundle manifests and metadata, then validate generated files.