Update MineOS docs (#1034)

We create again a dedicated login user, to work around the login issue, with MineOS not supporting the new default yescrypt password hashing algorithm. Add an info about how to change the password, since it is required to explicitly define SHA512 as hashing algorithm.

Add an info about supported Minecraft versions based on available Java versions.

docs/software/gaming.md

@@ -125,8 +125,14 @@ MineOS allows you to create multiple Minecraft servers with ease, using a simple
 
     - URL: `https://<your.IP>:8443`  
       You can safely ignore the certificate "warning" if one appears.
-    - Username: `root`
-    - Password: The same as your root login password. Default is `dietpi`
+    - Username: `mineos`
+    - Password = `<globalSoftwarePassword>` (default: `dietpi`)
+
+    To change the password to `myPassword`, run the following command:
+
+    ```sh
+    sudo chpasswd --crypt-method SHA512 <<< 'mineos:myPassword'
+    ```
 
 === "1st run setup"
 
@@ -144,6 +150,10 @@ MineOS allows you to create multiple Minecraft servers with ease, using a simple
 
     Your server should now be running, on the default port 25565.
 
+    !!! warning "Minecraft Java version requirements"
+        Note that Minecraft 1.20.5 and above requires Java 21, which is available on Debian Trixie/testing only, or with a custom Java installation.  
+        ARMv6 RPi models (RPi 1 and Zero 1) can only run Minecraft 1.16 or older, as newer Java versions do not support ARMv6 with Hotspot VM anymore.
+
 ***
 
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