Run go mod tidy for Go 1.17 and adopt new build tag format

.gitignore

@@ -1,3 +1,4 @@
+.DS_Store
 .vscode
 *.log
 *.srl

README.md

@@ -90,7 +90,7 @@ To run tests:
     make test
 
     # Option 2: run unit & integration tests in a Docker container
-    GO_VERSION=1.16 make docker-test
+    GO_VERSION=1.17 make docker-test
 
     # Open coverage information in browser
     go tool cover -html coverage-merged.out

certloader/certstore_disabled.go

@@ -1,4 +1,4 @@
-// +build !darwin,!windows
+//go:build !darwin && !windows
 
 /*-
  * Copyright 2018 Square Inc.

certloader/certstore_enabled.go

@@ -1,4 +1,4 @@
-// +build darwin windows
+//go:build darwin || windows
 
 /*-
  * Copyright 2018 Square Inc.

certloader/pkcs11_disabled.go

@@ -1,4 +1,4 @@
-// +build !cgo nopkcs11
+//go:build !cgo || nopkcs11
 
 /*-
  * Copyright 2018 Square Inc.

certloader/pkcs11_enabled.go

@@ -1,4 +1,4 @@
-// +build cgo,!nopkcs11
+//go:build cgo && !nopkcs11
 
 /*-
  * Copyright 2018 Square Inc.

certloader/pkcs11_test.go

@@ -1,4 +1,4 @@
-// +build cgo
+//go:build cgo
 
 /*-
  * Copyright 2018 Square Inc.

go.mod

@@ -34,4 +34,35 @@ require (
 	gopkg.in/alecthomas/kingpin.v2 v2.2.6
 )
 
-go 1.16
+require (
+	github.com/Masterminds/sprig v2.22.0+incompatible // indirect
+	github.com/alecthomas/template v0.0.0-20190718012654-fb15b899a751 // indirect
+	github.com/beorn7/perks v1.0.1 // indirect
+	github.com/cespare/xxhash/v2 v2.1.1 // indirect
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/fatih/color v1.9.0 // indirect
+	github.com/gogo/protobuf v1.2.1 // indirect
+	github.com/golang/protobuf v1.5.2 // indirect
+	github.com/google/uuid v1.1.2 // indirect
+	github.com/klauspost/cpuid/v2 v2.0.6 // indirect
+	github.com/libdns/libdns v0.2.1 // indirect
+	github.com/mattn/go-colorable v0.1.4 // indirect
+	github.com/mattn/go-isatty v0.0.12 // indirect
+	github.com/matttproud/golang_protobuf_extensions v1.0.1 // indirect
+	github.com/miekg/dns v1.1.42 // indirect
+	github.com/mitchellh/reflectwalk v1.0.1 // indirect
+	github.com/pkg/errors v0.9.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/prometheus/client_model v0.2.0 // indirect
+	github.com/prometheus/procfs v0.6.0 // indirect
+	go.uber.org/atomic v1.7.0 // indirect
+	go.uber.org/multierr v1.6.0 // indirect
+	go.uber.org/zap v1.17.0 // indirect
+	golang.org/x/crypto v0.0.0-20210513164829-c07d793c2f9a // indirect
+	golang.org/x/net v0.0.0-20210525063256-abc453219eb5 // indirect
+	golang.org/x/text v0.3.6 // indirect
+	google.golang.org/protobuf v1.26.0 // indirect
+	gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b // indirect
+)
+
+go 1.17

socket/launchd_disabled.go

@@ -1,4 +1,4 @@
-// +build !darwin
+//go:build !darwin
 
 /*-
  * Copyright 2019 Square Inc.

socket/launchd_enabled.go

@@ -1,4 +1,4 @@
-// +build darwin
+//go:build darwin
 
 /*-
  * Copyright 2019 Square Inc.

socket/systemd_disabled.go

@@ -1,4 +1,4 @@
-// +build !linux
+//go:build !linux
 
 /*-
  * Copyright 2019 Square Inc.

socket/systemd_enabled.go

@@ -1,4 +1,4 @@
-// +build linux
+//go:build linux
 
 /*-
  * Copyright 2019 Square Inc.

unix.go

@@ -1,4 +1,4 @@
-// +build !windows
+//go:build !windows
 
 /*-
  * Copyright 2015 Square Inc.