Allow messages to be complex on Discord recipe

[lucasmezencio]

Q	A
Bug fix?	Yes
New feature?	No
BC breaks?	No
Deprecations?	No
Fixed tickets	N/A

Do not forget to add notes about your changes to CHANGELOG.md

---

Hey @chapterjason thanks a lot for your previous fix, but it ended up to unable user to send 'complex' messages, just like this:

set('discord_notify_text', function () {
    return [
        'attachments' => [
            [
                'title' => get('application') . ' Application Has Started Deploying...',
                'fields' => [
                    [
                        'title' => 'Environment',
                        'value' => get('stage'),
                        'short' => true
                    ],
                    [
                        'title' => 'Branch',
                        'value' => get('branch') ?: 'master',
                        'short' => true
                    ],
                    [
                        'title' => 'Deployer',
                        'value' => get('user'),
                        'short' => true
                    ],
                ],
            ],
        ],
    ];
});

Because you set every single message as text. So I'm writing this PR just to get back to default messages with the text index in case user don't want to send complex messages. 🙂

@antonmedv let me know if you agree with this. Thank you guys!

[chapterjason]

Hey, I didn't know that was possible, but good to know. 👍

[chapterjason]

Looks good to me.

[lucasmezencio]

@chapterjason yay! 🎉