build-sys: replace gofmt.sh with `make fmt`

Signed-off-by: Alejandro Mery <amery@jpi.io>

Makefile

@@ -0,0 +1,15 @@
+.PHONY: all fmt build test
+
+GO ?= go
+
+all: fmt build
+
+fmt:
+	$(GO) fmt ./...
+	$(GO) mod tidy || true
+
+build:
+	$(GO) get -v ./...
+
+test:
+	$(GO) test -v ./...

gofmt.sh

@@ -1,4 +0,0 @@
-#!/bin/sh
-
-BASE="$(dirname "$0")"
-exec gofmt -l -w -e -s -- $(find "$BASE" -type f -name '*.go')