Get category announcement list | 获取版块公告列表

{
    "code": 20000,
    "data": [
        {
            "category_id": 1,
            "content": "版块公告内容",
            "created_at": "2024-01-01 00:00:00",
            "id": 1,
            "is_pinned": true,
            "title": "版块公告标题",
            "updated_at": "2024-01-01 00:00:00",
            "username": "moderator"
        }
    ],
    "err_code": "string",
    "msg": null
}