Add NEWS entry for mcrypt changes

Author: nikic

NEWS

@@ -21,6 +21,11 @@ PHP NEWS
 - Mail:
  . Fixed bug #66535 (Don't add newline after X-PHP-Originating-Script) (Tjerk)
 
+- Mcrypt:
+ . No longer allow invalid key sizes, invalid IV sizes or missing required IV
+ in mcrypt_encrypt, mcrypt_decrypt and the deprecated mode functions.
+ (Nikita)
+
 - MySQLi:
  . Fixed bug #66762i (Segfault in mysqli_stmt::bind_result() when link closed)
  (Remi)