Add samples to get project limits

Author: haphan

samples/compute/v2/limits/get_limits.php

@@ -0,0 +1,18 @@
+<?php
+
+require 'vendor/autoload.php';
+
+$openstack = new OpenStack\OpenStack([
+    'authUrl' => '{authUrl}',
+    'region'  => '{region}',    
+    'user'    => [
+        'id'       => '{userId}',
+        'password' => '{password}'
+    ],
+    'scope'   => ['project' => ['id' => '{projectId}']]
+]);
+
+$compute = $openstack->computeV2(['region' => '{region}']);
+
+/** @var \OpenStack\Compute\v2\Models\Limit $limit */
+$limit = $compute->getLimits();