from_school: wifi: add notice on Android 11+ temporary incompatibility

Signed-off-by: Charles Decoux <charles@cri.epita.fr>

docs/from_school/wifi.md

@@ -16,6 +16,10 @@ To connect on `IONIS`, follow these steps:
 1. Connect to the `IONIS` WiFi hotspot
 2. You will be asked for your logins. You need to log with your EPITA email address and *Bocal* password.
 
+:::danger
+**Due to a misconfiguration of the access points, it is no longer possible to connect to IONIS WiFi on Android 11 and higher**
+:::
+
 ## Arch Linux configuration
 
 This section assumes you want to connect to the IONIS WiFi on an Arch Linux