Update Makefile (#14195)

`make searchengine-mocks` was failing due to not finding `mockery`, although it was installed.

Makefile

@@ -236,7 +236,7 @@ einterfaces-mocks: ## Creates mock files for einterfaces.
 
 searchengine-mocks: ## Creates mock files for searchengines.
 	env GO111MODULE=off go get -u github.com/vektra/mockery/...
-	$(GOPATH)/bin/mockery -dir services/searchengine -all -output services/searchengine/mocks -note 'Regenerate this file using `make searchengine-mocks`.'
+	$(GOBIN)/mockery -dir services/searchengine -all -output services/searchengine/mocks -note 'Regenerate this file using `make searchengine-mocks`.'
 
 pluginapi: ## Generates api and hooks glue code for plugins
 	$(GO) generate $(GOFLAGS) ./plugin