add goimports to tools

Author: jackofallops

tools/generator-go-sdk/GNUmakefile

@@ -1,6 +1,6 @@
 default: build
 
-build:
+build: tools
 	go build .
 
 fmt:
@@ -13,7 +13,7 @@ test: build
 	go test -v ./...
 
 tools:
-	@echo "==> no tools required at this time."
+	@go install golang.org/x/tools/cmd/goimports@latest
 
 .PHONY: build fmt run test tools