New attachment type in Instagram

[Nick97-git]

New attachment type in Instagram ("unsupported_type"). I guess need to add it as a new attachment type in MessagingAttachment. Also, there's a share type of attachment, but unfortunately I don't have an example of such event.

{
    "object": "instagram",
    "entry": [
        {
            "time": 1668022334834,
            "id": "17841452691600098",
            "messaging": [
                {
                    "sender": {
                        "id": "5614879045272581"
                    },
                    "recipient": {
                        "id": "17841452691600098"
                    },
                    "timestamp": 1668022333735,
                    "message": {
                        "mid": "aWdfZAG1faXRlbToxOklHTWVzc2FnZAUlEOjE3ODQxNDUyNjkxNjAwMDk4OjM0MDI4MjM2Njg0MTcxMDMwMDk0OTEyODUyNTYwOTEwODQ0ODU4MjozMDc2OTU4MTA5OTY0OTI5MzAzMjAwODc1MDUxMTE2MTM0NAZDZD",
                        "attachments": [
                            {
                                "type": "unsupported_type",
                                "payload": {
                                    "url": "https://lookaside.fbsbx.com/ig_messaging_cdn/?asset_id=17997515821557846&signature=AbyoRMtwJfAwfS_JCQkUSk4cdnDbIxMpTQXNWXt1D5Y9DEBSrgaz6PUk279coBxpvYHihuOmA1dxxabr6j0XitFYd21z2PaGBG82_AH9WFAbok5IY3cDhSTWb8LRadklr0IOm8UP0O8RZnWI4IiUfDuD19-CdVWih_byfkU5WUJTUGJi6PkuOA0rzdyG4O9fOPAshk8gx631mtlydnq63ILMPzyM8sc"
                                }
                            }
                        ]
                    }
                }
            ]
        }
    ]
}

[nbartels]

The current MessagingAttachment implementation already supports the unsupported_type, but the convenience method to check the type easily is missing. I added this in the commit above. So, you can already work with this kind of attachment, but in the next release it will be a bit more easy.