Bug: update class not checking request() response adequately

[cameronterry]

The affected code is:

dark-matter/dark-matter/class-dm-pluginupdate.php

Lines 192 to 194 in 349538e

	$data = $this->request();
	$data->new_version = $data->version;
	$data->package = $data->download_url;

This can cause an error:

Fatal error: Uncaught error: Attempt to assign property "new_version" on bool