return HandlerStack for BC (#391)

* return HandlerStack for Backward Compatibility - #382

Author: k0ka

src/Common/Transport/HandlerStack.php

@@ -0,0 +1,14 @@
+<?php
+
+namespace OpenStack\Common\Transport;
+
+/**
+ * @deprecated use \OpenStack\Common\Transport\HandlerStackFactory instead
+ */
+class HandlerStack
+{
+    public static function create(callable $handler = null): \GuzzleHttp\HandlerStack
+    {
+        return HandlerStackFactory::create($handler);
+    }
+}