Add Makefile with generate, lint, and test targets

Author: xaionaro@dx.center

Makefile

@@ -0,0 +1,11 @@
+.PHONY: generate lint test
+
+generate:
+	git submodule update --init
+	go generate ./pkg/gen/
+
+lint:
+	go run github.com/golangci/golangci-lint/cmd/golangci-lint@latest run ./...
+
+test:
+	go test ./...