docs: add ZIP_TYPE environment variables

README.md

@@ -178,6 +178,14 @@ Set your password to encrypt Zip archive. Note that the password will always be
 
 Default: `WHEREISMYPASSWORD?`
 
+#### ZIP_TYPE
+
+Because the `zip` format is less secure, we offer archives in `7z` format for those who seek security.
+
+It should be noted that the password for bitwardenrs is encrypted before it is sent to the server. The server does not have plaintext passwords, so the `zip` format is good enough for basic encryption needs.
+
+Default: `zip` (only support `zip` and `7z` format)
+
 #### BACKUP_KEEP_DAYS
 
 Only keep last a few days backup files in the storage system. Set to `0` to keep all backup files.

README_zh.md

@@ -180,6 +180,14 @@ Rclone 远程名称，你可以自己修改命名。
 
 默认值：`WHEREISMYPASSWORD?`
 
+#### ZIP_TYPE
+
+因为 `zip` 格式安全性较低，我们为追求安全的人提供 `7z` 格式的存档。
+
+需要说明的是，bitwardenrs 的密码在发送到服务器前就已经加密了。服务器没有保存明文密码，所以 `zip` 格式已经可以满足基本的加密需求。
+
+默认值：`zip` (只支持 `zip` 和 `7z` 格式)
+
 #### BACKUP_KEEP_DAYS
 
 在远程存储系统中保留最近 X 天的备份文件。设置为 `0` 会保留所有备份文件。