add annotation to RedisClientInterface

Author: palicao

src/Client/RedisClientInterface.php

@@ -1,9 +1,13 @@
-<?php
-declare(strict_types=1);
-
-namespace Palicao\PhpRedisTimeSeries\Client;
-
-interface RedisClientInterface
-{
-    function executeCommand(array $params);
-}
+<?php
+declare(strict_types=1);
+
+namespace Palicao\PhpRedisTimeSeries\Client;
+
+interface RedisClientInterface
+{
+    /**
+     * @param array $params
+     * @return mixed
+     */
+    public function executeCommand(array $params);
+}