Add to zendesk.Organization struct some missing fields

[gal1996]

add

• ExtrenalId
• Details
• Notes

  type Organization struct {
  ID                 int64                  `json:"id,omitempty"`
  ExternalId         string                 `json:"external_id,omitempty"`
  URL                string                 `json:"url,omitempty"`
  Name               string                 `json:"name"`
  Details            string                 `json:"details,omitempty"`
  DomainNames        []string               `json:"domain_names"`
  GroupID            int64                  `json:"group_id"`
  SharedTickets      bool                   `json:"shared_tickets"`
  SharedComments     bool                   `json:"shared_comments"`
  Tags               []string               `json:"tags"`
  Notes              string                 `json:"notes,omitempty"`
  CreatedAt          time.Time              `json:"created_at,omitempty"`
  UpdatedAt          time.Time              `json:"updated_at,omitempty"`
  OrganizationFields map[string]interface{} `json:"organization_fields,omitempty"`
  }
  }

[nukosuke]

fixed by #233 if any problem occurs, reopen this issue or open new one