fix path

vendor/go-httpheader/Makefile

@@ -0,0 +1,15 @@
+help:
+	@echo "test             run test"
+	@echo "lint             run lint"
+
+.PHONY: test
+test:
+	go test -v -cover -coverprofile cover.out
+	go tool cover -html=cover.out -o cover.html
+
+.PHONY: lint
+lint:
+	gofmt -s -w .
+	goimports -w .
+	golint .
+	go vet