[css-sizing-3] Update Changes list.

Author: fantasai

css-sizing-3/Overview.bs

@@ -10,6 +10,8 @@ TR: https://www.w3.org/TR/css-sizing-3/
 Issue Tracking: CSSWG GitHub https://github.com/w3c/csswg-drafts/issues
 Editor: Tab Atkins, Google, http://xanthir.com/contact/, w3cid 42199
 Editor: Elika J. Etemad / fantasai, Invited Expert, http://fantasai.inkedblade.net/contact, w3cid 35400
+Previous version: https://www.w3.org/TR/2021/WD-css-sizing-3-20210317/
+Previous version: https://www.w3.org/TR/2020/WD-css-sizing-3-20201218/
 Previous version: https://www.w3.org/TR/2020/WD-css-sizing-3-20201023/
 Previous version: https://www.w3.org/TR/2019/WD-css-sizing-3-20190522/
 Previous version: https://www.w3.org/TR/2018/WD-css-sizing-3-20180304/
@@ -1313,11 +1315,25 @@ Changes</h2>
 <h3 class=no-num id="changes-recent">
 Recent Changes</h3>
 
-	There have only been minor mostly-editorial fixes since the
-	<a href="https://www.w3.org/TR/2020/WD-css-sizing-3-20201023/">23 October 2020 Working Draft</a>,
-	including renaming replaced element “intrinsic” dimensions to “natural” dimensions
-	in order to avoid confusion with [=intrinsic sizes=]
-	(see <a href="https://github.com/w3c/csswg-drafts/issues/4961">Issue 4961</a>).
+
+	<p>
+		Changes since the <a href="https://www.w3.org/TR/2020/WD-css-sizing-3-20201218/">18 December 2020 Working Draft</a> include:
+
+	<ul>
+		<li>
+			Fixed various errors in definition of max-content sizes of replaced elements
+			in [[#intrinsic-sizes]].
+			(<a href="https://github.com/w3c/csswg-drafts/issues/6072">Issue 6072</a>)
+		<li>
+			Added missing statement handling [=min-content constraint=]
+			to definition of [=fit-content size=].
+		<li>
+			Renamed replaced element “intrinsic” dimensions to “natural” dimensions
+			in order to avoid confusion with [=intrinsic sizes=]
+			(see <a href="https://github.com/w3c/csswg-drafts/issues/4961">Issue 4961</a>).
+		<li>
+			Various other minor editorial fixes and improvements.
+	</ul>
 
 	<p>
 		Major changes since the <a href="https://www.w3.org/TR/2019/WD-css-sizing-3-20190522/">22 May 2019 Working Draft</a> include: