Add a change log entry for 1.13.3

Author: jgonggrijp

index.html

@@ -2798,6 +2798,20 @@ <h2 id="notes">Notes</h2>
 
       <h2 id="changelog">Change Log</h2>
 
+      <p id="1.13.3">
+        <b class="header">1.13.3</b> &mdash; <small><i>April 23, 2022</i></small> &mdash; <a href="https://github.com/jashkenas/underscore/compare/1.13.2...1.13.3">Diff</a> &mdash; <a href="https://cdn.statically.io/gh/jashkenas/underscore/1.13.3/index.html">Docs</a><br />
+        <ul>
+          <li>
+            Fixes a compatibility issue with ExtendScript.
+          </li>
+          <li>
+            Various improvements to testing and continuous integration,
+            including the addition of security scanning and a reduced carbon
+            footprint.
+          </li>
+        </ul>
+      </p>
+
       <p id="1.13.2">
         <b class="header">1.13.2</b> &mdash; <small><i>December 16, 2021</i></small> &mdash; <a href="https://github.com/jashkenas/underscore/compare/1.13.1...1.13.2">Diff</a> &mdash; <a href="https://cdn.statically.io/gh/jashkenas/underscore/1.13.2/index.html">Docs</a><br />
         <ul>