dos: Document MariaDB support in README (#737)

Mention MariaDB in the database feature list. Install docs and TypeORM
already support type=mariadb; the app uses the mysql2 driver.

README.md

@@ -34,7 +34,7 @@ Certd® 是一个免费的全自动证书管理系统，让你的网站证书永
 * **多种通知方式**: 邮件通知、webhook通知、企微、钉钉、飞书、anpush等多种通知方式
 * **私有化部署**: 数据保存本地，安装简单快捷，镜像由Github Actions构建，过程公开透明
 * **多重安全保障**: 授权加密，站点隐藏，2FA，密码防爆破等多重安全保障
-* **多数据库支持**：支持SQLite、PostgreSQL、MySQL
+* **多数据库支持**：支持SQLite、PostgreSQL、MySQL、MariaDB
 * **开放接口支持**： 提供RESTful API接口，方便集成到其他系统
 * **站点证书监控**： 定时监控网站证书的过期时间
 * **多用户管理**： 用户可以管理自己的证书流水线

README_en.md

@@ -31,7 +31,7 @@ This project not only supports automated certificate application but also automa
 * Multiple notification methods, including email, webhook, WeChat Work, DingTalk, Lark, and anpush.
 * On-premises deployment, local data storage, simple and quick installation. Images are built by Github Actions, with a transparent process.
 * Multiple security measures, including authorization encryption, site hiding, 2FA, and password brute-force protection.
-* Supports multiple databases such as SQLite, PostgreSQL, and MySQL.
+* Supports multiple databases such as SQLite, PostgreSQL, MySQL, and MariaDB.
 * Open API support.
 * Site certificate monitoring.
 * Multi-user management.