[css-values-4] Update Changes list

Author: fantasai

css-values-4/Overview.bs

@@ -2666,6 +2666,8 @@ Changes</h2>
 
 	<ul>
 		<li>Added the ''vi'', ''vb'', ''ic'', ''cap'', ''lh'' and ''rlh'' units.
+		<li>Added ''min()'' and ''max()'' functional notations.
+		<li>Added unit arithmetic to ''calc()''.
 	</ul>
 
 <h2 class="no-num" id="sec-pri">