User-Agent doesn't use composer.json as source

[ivan-section-io]

The hard-coded string used for the user-agent, is not always updated when it should be.
https://github.com/section-io/magento-metrics/blob/master/Helper/Aperture.php#L187

The user-agent shouldn't rely on a human updating source code to stay accurate.

Add something like:

$composerJson = file_get_contents(dirname(__FILE__) . "/../composer.json");
if ($composerJson === false) {
throw new Exception("Unable to read composer.json file!");
}
$composer = json_decode($composerJson);
if ($composer === null) {
throw new Exception("JSON parse error while reading composer.json!");
}
if (!isset($composer->version)) {
throw new Exception("Version field must be set in composer.json!");
}
$release = $composer->version;