refactor(backend): 更新微信相关服务的命名空间

- 将 SixShop\Extension\wechat 修改为 SixShop\Wechat

src/PaymentProvider.php

@@ -13,7 +13,7 @@ use SixShop\Payment\Contracts\PaymentResponse;
 use SixShop\Payment\Entity\ExtensionPaymentEntity;
 use SixShop\Payment\Enum\PaymentBizEnum;
 use SixShop\Payment\Enum\PaymentStatusEnum;
-use SixShop\Extension\wechat\Facade\WechatUser;
+use SixShop\Wechat\Facade\WechatUser;
 use SixShop\WechatPay\Trait\ApiTrait;
 use WeChatPay\Crypto\Rsa;
 use WeChatPay\Formatter;