ensure mailpit for unit test

Makefile

@@ -184,7 +184,7 @@ jest: $(NODE_DEPS)
 	$(MAKE) ensure-yarn
 	yarn run jest $(JEST_ARGS)
 
-test: $(NODE_DEPS) jest ## Run all unit tests
+test: $(NODE_DEPS) jest $(BIN_DIR)/tools/mailpit ## Run all unit tests
 	rm -rf $(PWD)/test/coverage/unit
 	mkdir -p $(PWD)/test/coverage/unit
 	go test -coverpkg=./... -short ./... -args -test.gocoverdir=$(PWD)/test/coverage/unit