use `go install` for tools

Golang 1.16 added better support for installing tools, without updating
go.mod files: https://blog.golang.org/go116-module-changes#TOC_4. .

GNUmakefile

@@ -90,21 +90,21 @@ bootstrap: deps lint-deps git-hooks # Install all dependencies
 deps:  ## Install build and development dependencies
 ## Keep versions in sync with tools/go.mod for now (see https://github.com/golang/go/issues/30515)
 	@echo "==> Updating build dependencies..."
-	GO111MODULE=on cd tools && go get github.com/hashicorp/go-bindata/go-bindata@bf7910af899725e4938903fb32048c7c0b15f12e
-	GO111MODULE=on cd tools && go get github.com/elazarl/go-bindata-assetfs/go-bindata-assetfs@234c15e7648ff35458026de92b34c637bae5e6f7
-	GO111MODULE=on cd tools && go get github.com/a8m/tree/cmd/tree@fce18e2a750ea4e7f53ee706b1c3d9cbb22de79c
-	GO111MODULE=on cd tools && go get gotest.tools/gotestsum@v0.4.2
-	GO111MODULE=on cd tools && go get github.com/hashicorp/hcl/v2/cmd/hclfmt@v2.5.1
-	GO111MODULE=on cd tools && go get github.com/golang/protobuf/protoc-gen-go@v1.3.4
-	GO111MODULE=on cd tools && go get github.com/hashicorp/go-msgpack/codec/codecgen@v1.1.5
+	go install github.com/hashicorp/go-bindata/go-bindata@bf7910af899725e4938903fb32048c7c0b15f12e
+	go install github.com/elazarl/go-bindata-assetfs/go-bindata-assetfs@234c15e7648ff35458026de92b34c637bae5e6f7
+	go install github.com/a8m/tree/cmd/tree@fce18e2a750ea4e7f53ee706b1c3d9cbb22de79c
+	go install gotest.tools/gotestsum@v0.4.2
+	go install github.com/hashicorp/hcl/v2/cmd/hclfmt@v2.5.1
+	go install github.com/golang/protobuf/protoc-gen-go@v1.3.4
+	go install github.com/hashicorp/go-msgpack/codec/codecgen@v1.1.5
 
 .PHONY: lint-deps
 lint-deps: ## Install linter dependencies
 ## Keep versions in sync with tools/go.mod (see https://github.com/golang/go/issues/30515)
 	@echo "==> Updating linter dependencies..."
-	GO111MODULE=on cd tools && go get github.com/golangci/golangci-lint/cmd/golangci-lint@v1.24.0
-	GO111MODULE=on cd tools && go get github.com/client9/misspell/cmd/misspell@v0.3.4
-	GO111MODULE=on cd tools && go get github.com/hashicorp/go-hclog/hclogvet@v0.1.3
+	go install github.com/golangci/golangci-lint/cmd/golangci-lint@v1.24.0
+	go install github.com/client9/misspell/cmd/misspell@v0.3.4
+	go install github.com/hashicorp/go-hclog/hclogvet@v0.1.3
 
 .PHONY: git-hooks
 git-dir = $(shell git rev-parse --git-dir)

tools/go.mod

 module github.com/hashicorp/nomad/tools
 
-go 1.15
+go 1.16
 
-require (
-	github.com/a8m/tree v0.0.0-20201026183218-fce18e2a750e
-	github.com/aws/aws-sdk-go v1.35.5
-	github.com/client9/misspell v0.3.4
-	github.com/elazarl/go-bindata-assetfs v1.0.1
-	github.com/golang/protobuf v1.3.4
-	github.com/golangci/golangci-lint v1.24.0
-	github.com/google/go-cmp v0.4.0 // indirect
-	github.com/hashicorp/go-bindata v3.0.8-0.20180209072458-bf7910af8997+incompatible
-	github.com/hashicorp/go-hclog/hclogvet v0.1.3
-	github.com/hashicorp/go-msgpack v1.1.5
-	github.com/hashicorp/hcl/v2 v2.5.1
-	github.com/kr/text v0.2.0 // indirect
-	github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e // indirect
-	github.com/onsi/ginkgo v1.12.0 // indirect
-	github.com/onsi/gomega v1.9.0 // indirect
-	github.com/stretchr/testify v1.5.1 // indirect
-	golang.org/x/tools v0.0.0-20200502202811-ed308ab3e770 // indirect
-	gopkg.in/check.v1 v1.0.0-20200227125254-8fa46927fb4f // indirect
-	gotest.tools/gotestsum v0.4.2
-)
+require github.com/aws/aws-sdk-go v1.37.26

tools/tools.go

-//+build tools
-
-// Package tools anonymously imports packages of tools used to build nomad.
-// See the GNUMakefile for 'go get` commands.
-package tools
-
-import (
-	_ "github.com/a8m/tree/cmd/tree"
-	_ "github.com/client9/misspell/cmd/misspell"
-	_ "github.com/elazarl/go-bindata-assetfs/go-bindata-assetfs"
-	_ "github.com/golang/protobuf/protoc-gen-go"
-	_ "github.com/golangci/golangci-lint/cmd/golangci-lint"
-	_ "github.com/hashicorp/go-bindata/go-bindata"
-	_ "github.com/hashicorp/go-hclog/hclogvet"
-	_ "github.com/hashicorp/go-msgpack/codec/codecgen"
-	_ "github.com/hashicorp/hcl/v2/cmd/hclfmt"
-	_ "gotest.tools/gotestsum"
-)