Creates an incident action item

curl --request POST \
  --url https://api.rootly.com/v1/incidents/{incident_id}/action_items \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/vnd.api+json' \
  --data '
{
  "data": {
    "attributes": {
      "summary": "<string>",
      "description": "<string>",
      "assigned_to_user_id": 123,
      "assigned_to_group_ids": [
        "<string>"
      ],
      "due_date": "<string>",
      "jira_issue_id": "<string>",
      "jira_issue_key": "<string>",
      "jira_issue_url": "<string>"
    }
  }
}
'

{
  "data": {
    "id": "<string>",
    "attributes": {
      "summary": "<string>",
      "created_at": "<string>",
      "updated_at": "<string>",
      "description": "<string>",
      "assigned_to": {
        "id": 123,
        "email": "<string>",
        "created_at": "<string>",
        "updated_at": "<string>",
        "first_name": "<string>",
        "last_name": "<string>",
        "full_name": "<string>",
        "full_name_with_team": "<string>",
        "time_zone": "<string>"
      },
      "assigned_to_group_ids": [
        "<string>"
      ],
      "due_date": "<string>",
      "jira_issue_id": "<string>",
      "jira_issue_key": "<string>",
      "jira_issue_url": "<string>"
    }
  }
}