Update CHANGELOG.

CHANGELOG

@@ -5,6 +5,9 @@ v0.6.2 (2010-xx-xx)
       - Strings: STRLEN
       - Lists  : LINSERT, RPUSHX, LPUSHX
 
+  * WATCH also accepts a single array parameter with the keys that should be 
+    monitored during a transaction.
+
   * Improved the behaviour of Predis\MultiExecBlock in certain corner cases.
 
   * Improved parameters checking for the SORT command.