Fix custom scalar

src/Appwrite/GraphQL/Types/Assoc.php

@@ -6,11 +6,11 @@ use GraphQL\Language\AST\Node;
 use GraphQL\Type\Definition\ScalarType;
 
 // https://github.com/webonyx/graphql-php/issues/129#issuecomment-309366803
-class Assoc extends Json
+class Assoc extends ScalarType
 {
     public function __construct()
     {
-        ScalarType::__construct([
+        parent::__construct([
             'name' => 'Assoc',
             'description' => 'The `Assoc` scalar type represents associative array values.',
         ]);