rn-121: add Štěpán Němec among the helpers

Author: chriscool

Diff for: rev_news/drafts/edition-121.md

@@ -426,4 +426,4 @@ Christian Couder &lt;<christian.couder@gmail.com>&gt;,
 Jakub Narębski &lt;<jnareb@gmail.com>&gt;,
 Markus Jansen &lt;<mja@jansen-preisler.de>&gt; and
 Kaartic Sivaraam &lt;<kaartic.sivaraam@gmail.com>&gt;
-with help from Peter Krefting.
+with help from Peter Krefting and Štěpán Němec.