Update configuration.mdx

Author: wmnnd

src/content/docs/en/configuration.mdx

@@ -26,10 +26,10 @@ When you start Keila for the first time, a root user is created. If you don’t
 specify otherwise, a user with a random password is created printed to
 stdout.
 
-| Variable         | Required | Default          | Description                     |
-| ---------------- | -------- | ---------------- | ------------------------------- |
-| `KEILA_USER`     |          | `root@localhost` | Email address for the root user |
-| `KEILA_PASSWORD` |          | _random_         | Password for the root user      |
+| Variable         | Required | Default          | Description                                        |
+| ---------------- | -------- | ---------------- | -------------------------------------------------- |
+| `KEILA_USER`     |          | `root@localhost` | Email address for the root user                    |
+| `KEILA_PASSWORD` |          | _random_         | Password for the root user. At least 10 characters |
 
 ## URL