Forge Maven Skin: line numbers failing when using maven-site-plugin 3.3

When the "sourceLineNumbers" setting is on and the site is rendered by maven-site-plugin version 3.3, no source line numbers are shown.

The reason is this piece of code in site.vm:863
$bodyContent.replaceAll( "<div class=\"source\"><pre>", "<div class=\"source\"><pre class=\"$sourceStyle\">" )

maven-site-plugin version 3.1 renders html markup "<div class=\"source\"><pre>"
maven-site-plugin version 3.3 renders html markup "<div class=\"source\">
<pre>"

Note the pre on the next line so the replaceAll is not finding anything!