def update(key, value)
      request_data = {:key => key, :value => value}
      request_data[:expire] = @expire if @expire
      request = prepare_request :PUT, request_data.to_json
      Response.new(execute_request(request))
    end
def update(key, value)
      request_data = {:key => key, :value => value}
      request_data[:expire] = @expire if @expire
      request = prepare_request :PUT, request_data.to_json
      Response.new(execute_request(request))
    end
Update data stored at a given SAM key

 @param [String] key of the data to update
 @param [String, Hash, Array] data to be stored at the key
 @return [Response] response object holding the file and some metadata

 @raise [NSISam::Errors::Client::KeyNotFoundError] when the key doesn't exists
 @raise [NSISam::Errors::Client::AuthenticationError] when user and password doesn't match

 @example
   nsisam.update("my key", "my value")