Add GOBIN to PATH in Makefile (#485)

Author: alexshtin

Makefile

@@ -37,6 +37,9 @@ ifndef GOPATH
 GOPATH := $(shell go env GOPATH)
 endif
 
+GOBIN := $(if $(shell go env GOBIN),$(shell go env GOBIN),$(GOPATH)/bin)
+export PATH := $(GOBIN):$(PATH)
+
 MODULE_ROOT := github.com/temporalio/temporal
 BUILD := ./build
 COLOR := "\e[1;36m%s\e[0m\n"