Fix ClientBuilder - pass correct argument for Elasticsearch\Endpoints…

…\MsearchTemplate::__construct. (#605)

src/Elasticsearch/ClientBuilder.php

@@ -509,7 +509,7 @@ public function build()
 
             $this->endpoint = function ($class) use ($serializer) {
                 $fullPath = '\\Elasticsearch\\Endpoints\\' . $class;
-                if ($class === 'Bulk' || $class === 'Msearch' || $class === 'MPercolate') {
+                if ($class === 'Bulk' || $class === 'Msearch' || $class === 'MsearchTemplate' || $class === 'MPercolate') {
                     return new $fullPath($serializer);
                 } else {
                     return new $fullPath();