fix: dynamic properties

Author: JoyceBabu

src/Snowflake/Store/FileStore.php

@@ -7,7 +7,8 @@
 
 class FileStore implements StoreInterface
 {
-    public function __construct($cacheDir)
+    private string $cacheDir;
+    public function __construct(string $cacheDir)
     {
         $this->cacheDir = $cacheDir;
 

src/Snowflake/Store/RedisStore.php

@@ -7,10 +7,10 @@
 
 class RedisStore implements StoreInterface
 {
-    private $backend;
-    public function __construct(\Redis $redis)
+    private \Redis $backend;
+    public function __construct(\Redis $backend)
     {
-        $this->backend = $redis;
+        $this->backend = $backend;
     }
 
     private function getLuaScript()