Update RELEASE-NOTES.md

Author: JeroenDeDauw

RELEASE-NOTES.md

@@ -49,6 +49,7 @@ Other breaking changes:
 * Renamed `Claim\ClaimGuid` to `Statement\StatementGuid`, leaving a b/c alias in place
 * Renamed `Claim\ClaimGuidParser` to `Statement\StatementGuidParser`, leaving a b/c alias in place
 * Renamed `Claim\ClaimGuidParsingException` to `Statement\StatementGuidParsingException`, leaving a b/c alias in place
+* Derprecated `Snaks` in favour of `SnakList`
 
 ## Version 2.6.1 (2015-04-25)