Remove mention to a dead demo instance

README.md

@@ -19,18 +19,6 @@ The project page (issue, wiki, etc) is here:
 
 A mailing list is available, for both users and developers: https://listes.illyse.org/wws/info/si
 
-
-Demo
-====
-
-A demo of COIN is publicly available at https://coin-dev.illyse.org
-
-- Login: ffdn
-- Password: internet
-
-This user account has access to the administration interface.
-
-
 Extending Coin
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