PHP cURLを使用してPOSTリクエストでJSONデータを送信するにはどうすればよいですか?

<?php

$url = "http://domain/OnLeagueRest/resources/onleague/Account/CreditAccount";
$data = json_encode([
    'userID' => 'a7664093-502e-4d2b-bf30-25a2b26d6021',
    'itemKind' => 0,
    'value' => 1,
    'description' => 'Saude',
    'itemID' => '03e76d0a-8bab-11e0-8250-000c29b481aa'
]);

$ch = curl_init($url);
curl_setopt($ch, CURLOPT_HEADER, false);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER,
        array("Content-type: application/json"));
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, $data);

$response = curl_exec($ch);

$status = curl_getinfo($ch, CURLINFO_HTTP_CODE);

if ( $status != 201 ) {
    die("Error: call to URL $url failed with status $status, response $response, curl_error " . curl_error($ch) . ", curl_errno " . curl_errno($ch));
}

curl_close($ch);

$response = json_decode($response, true);

?>