doc: fix changelog anchor to v8.7.0

PR-URL: nodejs/node#16165
Reviewed-By: Vse Mozhet Byt <vsemozhetbyt@gmail.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

Author: lzhang

doc/changelogs/CHANGELOG_V8.md

@@ -6,7 +6,7 @@
 </tr>
 <tr>
 <td>
-<a href="#8.6.0">8.7.0</a><br/>
+<a href="#8.7.0">8.7.0</a><br/>
 <a href="#8.6.0">8.6.0</a><br/>
 <a href="#8.5.0">8.5.0</a><br/>
 <a href="#8.4.0">8.4.0</a><br/>