added change to upgrade file

UPDATE.md

@@ -71,6 +71,11 @@ RC4 to RC5
 * To avoid hidden naming collisions, the AbstractType does not try to define
   the name of form types magically. You now need to implement the `getName()`
   method explicitly when creating a custom type.
+  
+* Renamed some methods to follow the naming conventions:
+
+    Session::getAttributes() -> Session::all()
+    Session::setAttributes() -> Session::replace()
 
 RC3 to RC4
 ----------