doc: update CHANGELOG_V18.md

PR-URL: nodejs#43298
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>

Author: panva

doc/changelogs/CHANGELOG_V18.md

@@ -8,6 +8,7 @@
 </tr>
 <tr>
 <td>
+<a href="#18.3.0">18.3.0</a><br/>
 <a href="#18.2.0">18.2.0</a><br/>
 <a href="#18.1.0">18.1.0</a><br/>
 <a href="#18.0.0">18.0.0</a><br/>