Added mrkdwn_in field to attachments
Added mrkdwn_in field to attachments

To enable formatting on attachment fields, set the mrkdwn_in array in the attachment for each field to process.

$attachment->setMrkDwnIn("title");
$attachment->setMrkDwnIn("pretext");
$attachment->setMrkDwnIn("text");
SimonBackx/Slack-PHP-Webhook,SimonBackx/SlackPhp