Fix typo [ci skip]

Author: staabm

UPGRADING

@@ -352,7 +352,7 @@ PHP 8.0 UPGRADE NOTES
   . Added WeakMap.
     RFC: https://wiki.php.net/rfc/weak_maps
   . Added ValueError class.
-  . Any number of function parameters may not be replaced by a variadic
+  . Any number of function parameters may now be replaced by a variadic
     argument, as long as the types are compatible. For example, the following
     code is now allowed: