testpayload.json

{
  "type": "message",
  "attachments": [
    {
      "contentType": "application/vnd.microsoft.card.adaptive",
      "contentUrl": null,
      "content": {
        "$schema": "https://adaptivecards.io/schemas/adaptive-card.json",
        "type": "AdaptiveCard",
        "version": "1.0",
        "body": [
          {
            "type": "Container",
            "items": [
              {
                "type": "ColumnSet",
                "columns": [
                  {
                    "type": "Column",
                    "width": "auto",
                    "items": [
                      {
                        "type": "Image",
                        "url": "<actor_avatar_url>",
                        "size": "medium",
                        "style": "person"
                      }
                    ]
                  },
                  {
                    "type": "Column",
                    "width": "stretch",
                    "items": [
                      {
                        "type": "TextBlock",
                        "text": "<actor_display_name>",
                        "weight": "bolder",
                        "wrap": true
                      },
                      {
                        "type": "TextBlock",
                        "text": "<pull_request_title>",
                        "size": "large",
                        "weight": "bolder",
                        "wrap": true
                      },
                      {
                        "type": "TextBlock",
                        "text": "<pull_request_description>",
                        "wrap": true
                      }
                    ]
                  }
                ]
              }
            ]
          }
        ]
      }
    }
  ]
}