Creates a user email address

curl --request POST \
  --url https://api.rootly.com/v1/users/{user_id}/email_addresses \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/vnd.api+json' \
  --data '{
  "data": {
    "type": "user_email_addresses",
    "attributes": {
      "email": "<string>"
    }
  }
}'

{
  "data": {
    "id": "1020517b-323c-406d-9ed7-80075c0b7088",
    "type": "user_email_addresses",
    "attributes": {
      "user_id": 475,
      "email": "test@example.com",
      "primary": false,
      "created_at": "2025-05-29T17:49:27.677-07:00",
      "updated_at": "2025-05-29T17:49:27.677-07:00"
    }
  }
}