[css-images-3] Update Changes

Author: fantasai

css-images-3/Overview.bs

@@ -1988,6 +1988,15 @@ Changes</h2>
 <h3 id="changes-20191010">
 Changes Since the <a href="https://www.w3.org/TR/2019/CR-css-images-3-20191010/">10 October 2019 Candidate Recommendation</a></h3>
 
+	Significant changes since the <a href="https://www.w3.org/TR/2020/CRD-css-images-3-20201217/">17 December 2020 CR</a>:
+
+	* Specify ''pixelated'' to use smooth scaling from a [=nearest neighbor=] scale to the nearest pixel multiple,
+		in order to avoid distortion.
+		(<a href="https://github.com/w3c/csswg-drafts/issues/5837">Issue 5837</a>)
+	* Explicitly allow [=nearest neighbor=] as the implementation for ''crisp-edges'',
+		since this is what implementations currently do.
+		(<a href="https://github.com/w3c/csswg-drafts/issues/6038">Issue 6038</a>)
+
 	Significant changes since the <a href="https://www.w3.org/TR/2019/CR-css-images-3-20191010/">10 October 2019 CR</a>:
 
 	* Define handling of degenerate aspect ratios