[css-overflow-4] Update changelog

Author: frivoal

css-overflow-4/Overview.bs

@@ -1443,6 +1443,8 @@ Recent Changes</h3>
 			(<a href="https://github.com/w3c/csswg-drafts/issues/9368">Issue 9368</a>)
 		<li>Dropped the tentative <code>force</code> value for the 'scrollbar-gutter' property.
 			(<a href="https://github.com/w3c/csswg-drafts/issues/9815">Issue 9815</a>)
+		<li>Establish an Independent Formatting Context when ''continue: discard'' is used.
+			(<a href="https://github.com/w3c/csswg-drafts/issues/10323">Issue 10323</a>)
 	</ul>
 
 <h3 id="changes-l3">