v2.2.4

Add support for OAuth Client Credentials Flow

- public function getOAuthToken(string $code): Result
+ public function getOAuthToken(?string $code = null, string $grantType = GrantType::AUTHORIZATION_CODE, array $scopes = []): Result

use romanzipp\Twitch\Enums\GrantType;

$twitch = new romanzipp\Twitch;

$twitch->getOAuthToken(null, GrantType::CLIENT_CREDENTIALS, ['user:read']);