Simplify build tags associated with unsupported golang versions

internal/crypto/ptls/old.go

@@ -1,8 +1,8 @@
-// Copyright 2021 the Pinniped contributors. All Rights Reserved.
+// Copyright 2021-2023 the Pinniped contributors. All Rights Reserved.
 // SPDX-License-Identifier: Apache-2.0
 
-//go:build !go1.17
-// +build !go1.17
+//go:build !go1.19
+// +build !go1.19
 
 package ptls
 
@@ -10,6 +10,6 @@ func init() {
 	// cause compile time failure if an older version of Go is used
 	`Pinniped's TLS configuration makes assumptions about how the Go standard library implementation of TLS works.
 It particular, we rely on the server controlling cipher suite selection.  For these assumptions to hold, Pinniped
-must be compiled with Go 1.17+.  If you are seeing this error message, your attempt to compile Pinniped with an
+must be compiled with Go 1.19+.  If you are seeing this error message, your attempt to compile Pinniped with an
 older Go compiler was explicitly failed to prevent an unsafe configuration.`
 }

internal/testutil/tempdir.go

@@ -1,9 +1,6 @@
-// Copyright 2020-2022 the Pinniped contributors. All Rights Reserved.
+// Copyright 2020-2023 the Pinniped contributors. All Rights Reserved.
 // SPDX-License-Identifier: Apache-2.0
 
-//go:build !go1.14
-// +build !go1.14
-
 package testutil
 
 import (

internal/testutil/tempdir_go1.14.go

@@ -1,25 +0,0 @@
-// Copyright 2020-2022 the Pinniped contributors. All Rights Reserved.
-// SPDX-License-Identifier: Apache-2.0
-
-//go:build go1.14
-// +build go1.14
-
-package testutil
-
-import (
-	"io/ioutil" //nolint:staticcheck // ioutil is deprecated, but this file is for go1.14
-	"os"
-	"testing"
-
-	"github.com/stretchr/testify/require"
-)
-
-func TempDir(t *testing.T) string {
-	t.Helper()
-	dir, err := ioutil.TempDir("", "test-*")
-	require.NoError(t, err)
-	t.Cleanup(func() {
-		require.NoError(t, os.RemoveAll(dir))
-	})
-	return dir
-}