code: func (s *OrganizationsService) CreateOrgInvitation(ctx context.Context, org string, opt *CreateOrgInvitationOptions) (*Invitation, *Response, error) {
  	u := fmt.Sprintf("orgs/%v/invitations", org)
  
  	req, err := s.client.NewRequest("POST", u, opt)
  	if err != nil {
  		return nil, nil, err
  	}
  
  	// TODO: remove custom Accept header when this API fully launches.
  	req.Header.Set("Accept", mediaTypeOrganizationInvitationPreview)
  
  	var invitation *Invitation
  	resp, err := s.client.Do(ctx, req, &invitation)
  	if err != nil {
  		return nil, resp, err
  	}
  	return invitation, resp, nil
  }
docs: // CreateOrgInvitation invites people to an organization by using their GitHub user ID or their email address.
  // In order to create invitations in an organization,
  // the authenticated user must be an organization owner.
  //
  // https://developer.github.com/v3/orgs/members/#create-organization-invitation