doc: drop <b> of v20 changelog

PR-URL: #48649
Reviewed-By: Moshe Atlow <moshe@atlow.co.il>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Richard Lau <rlau@redhat.com>
Reviewed-By: Marco Ippolito <marcoippolito54@gmail.com>

doc/changelogs/CHANGELOG_V20.md

@@ -8,7 +8,7 @@
 </tr>
 <tr>
 <td>
-<b><a href="#20.4.0">20.4.0</a></b><br/>
+<a href="#20.4.0">20.4.0</a><br/>
 <a href="#20.3.1">20.3.1</a><br/>
 <a href="#20.3.0">20.3.0</a><br/>
 <a href="#20.2.0">20.2.0</a><br/>