Update changelog for developer

ChangeLog

@@ -150,6 +150,7 @@ Dolibarr better:
 - A new paramater sqlfilters was introduced to allow filter on any fields int the REST API. Few old parameters,
   no more required, were also removed. Use this new one if you were using one of them.
 - The trigger that activate or close a contract line is run on a contract line, not on contract.
+- Method commande->set_availability(user, availability_id) removed from commande class.
 
 Dolibarr 5.0 was frozen before PHP 7.1 was released. Unit tests are successful on PHP 7.1 but we don't have enough
 feedback to confirm all application is compatible. Current officiel supported PHP versions are PHP 5.3 to 7.0.