provide info about socket types on caravan page

docs/caravans.md

 # Caravans
 
-As with previous iterations of CCCamp, you will be able to purchase a *caravan ticket* and attend this year's Camp with a caravan/campervan. 
+As with previous iterations of CCCamp, you will be able to purchase a *caravan ticket* and attend this year's Camp with a caravan/campervan.
 
 If you're planning to attend CCCamp with a caravan, please keep the following in mind:
 
@@ -13,6 +13,7 @@ Note that preparations are still ongoing. Information is provided as accurately
 
 * There **won't** be water or sewage connections
 * There *might* be power connections
+  * Sockets provided will be 230V Schuko, no CEE!
 * There will *most probably* be network hubs
 
 ## Locations