[meta] update editors list for ES2020

Author: ljharb

spec.html

@@ -60,9 +60,8 @@ <h1>Contributing to this Specification</h1>
     <li>
       Editors:
       <ul>
-        <li><a href="mailto:brian.terlson at microsoft dot com">Brian Terlson</a> (<a href="https://twitter.com/bterlson">@bterlson</a>)</li>
-        <li><a href="mailto:bradley.meck at gmail dot com">Bradley Farias</a> (<a href="https://twitter.com/bradleymeck">@bradleymeck</a>)</li>
         <li><a href="mailto:ljharb at gmail dot com">Jordan Harband</a> (<a href="https://twitter.com/ljharb">@ljharb</a>)</li>
+        <li><a href="mailto:zenparsing at gmail dot com">Kevin Smith</a> (<a href="https://twitter.com/zenparsing">@zenparsing</a>)</li>
       </ul>
     </li>
     <li>