Use go mod to manage go tools

Makefile

SHELL := /bin/sh

BIN := bin

define ADD_TOOL_BINARY_RULE
TOOLS_BINARIES += $$(BIN)/$$(notdir $(1))
$$(lastword $$(TOOLS_BINARIES)):
	@go build -o $$@ $(1)
endef

TOOLS := $(shell go list -f '{{range .Imports}} {{- .}} {{end}}' tools.go)
$(foreach tool,$(TOOLS),$(eval $(call ADD_TOOL_BINARY_RULE,$(tool))))

.PHONY: fix-imports
fix-imports: tools
	@$(BIN)/goimports -l -w .

.PHONY: lint
lint: tools
	@$(BIN)/golangci-lint run ./...

tools: tidy $(TOOLS_BINARIES)

.PHONY: tidy
tidy:
	@go mod tidy

tools.go

//go:build tools
// +build tools

package main

import (
	_ "github.com/golangci/golangci-lint/cmd/golangci-lint"
	_ "golang.org/x/tools/cmd/goimports"
)