feat: add CartDriver interface

src/Drivers/Contracts/CartDriver.php

@@ -0,0 +1,28 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Wearepixel\Cart\Drivers\Contracts;
+
+interface CartDriver
+{
+    public function getSessionKey(): string;
+
+    public function setSessionKey(string $sessionKey): void;
+
+    public function getDriverName(): string;
+
+    public function getItems(): array;
+
+    public function putItems(array $items): void;
+
+    public function getConditions(): array;
+
+    public function putConditions(array $conditions): void;
+
+    public function clearItems(): void;
+
+    public function flush(): void;
+
+    public function getSessionModel(): mixed;
+}