[css-color-5][editorial] Update changes

Author: svgeesus

css-color-5/Overview.bs

@@ -2794,6 +2794,12 @@ to WCAG 2.1 <a href="https://www.w3.org/TR/WCAG21/#contrast-minimum">section 1.4
 Changes {#changes}
 =======
 
+<h3 id="changes-20220428">Since the <a href="https://www.w3.org/TR/2022/WD-css-color-5-20220428/">Working Draft of 28 April 2022</a></h3>
+
+<ul>
+	<li>Summarized what color-contrast() does, earlier in the description</li>
+</ul>
+
 <h3 id="changes-20211215">Since the <a href="https://www.w3.org/TR/2021/WD-css-color-5-20211215/">Working Draft of 15 December 2021</a></h3>
 
 <ul>