Update realase notes

Author: JeroenDeDauw

RELEASE-NOTES.md

@@ -68,9 +68,9 @@ Other breaking changes:
 * Deprecated `Entity::setId`, `Entity::newClaim` and `Entity::getAllSnaks`
 * Deprecated `Item::getClaims` in favour of `Item::getStatements`
 
-## Version 0.9.1 (2014-08-25)
+## Version 0.9.1 (2014-08-26)
 
-* Fixed fatal error: Can't inherit abstract function EntityDocument::getType() (previously declared abstract in Entity)
+* Fixed error caused by redeclaration of getType in `Entity`, after it already got defined in `EntityDocument`
 
 ## Version 0.9 (2014-08-15)