all: use Go 1.22 range-over-int

Updates #11058

Change-Id: I35e7ef9b90e83cac04ca93fd964ad00ed5b48430
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

clientupdate/clientupdate.go

@@ -436,7 +436,7 @@ func (up *Updater) updateDebLike() error {
 		return fmt.Errorf("apt-get update failed: %w; output:\n%s", err, out)
 	}
 
-	for i := 0; i < 2; i++ {
+	for range 2 {
 		out, err := exec.Command("apt-get", "install", "--yes", "--allow-downgrades", "tailscale="+ver).CombinedOutput()
 		if err != nil {
 			if !bytes.Contains(out, []byte(`dpkg was interrupted`)) {

clientupdate/clientupdate_test.go

@@ -663,7 +663,7 @@ func genTarball(t *testing.T, path string, files map[string]string) {
 
 func TestWriteFileOverwrite(t *testing.T) {
 	path := filepath.Join(t.TempDir(), "test")
-	for i := 0; i < 2; i++ {
+	for i := range 2 {
 		content := fmt.Sprintf("content %d", i)
 		if err := writeFile(strings.NewReader(content), path, 0600); err != nil {
 			t.Fatal(err)

clientupdate/distsign/distsign_test.go

@@ -445,7 +445,7 @@ type testServer struct {
 
 func newTestServer(t *testing.T) *testServer {
 	var roots []rootKeyPair
-	for i := 0; i < 3; i++ {
+	for range 3 {
 		roots = append(roots, newRootKeyPair(t))
 	}