Apply suggestion from @kbestak

Co-authored-by: Krešimir Beštak <86408271+kbestak@users.noreply.github.com>

Author: FloWuenne

workflows/molkart.nf

@@ -283,7 +283,7 @@ workflow MOLKART {
     //
     // Collate and save software versions
     //
-    def topic_versions = Channel.topic("versions")
+    def topic_versions = channel.topic("versions")
         .distinct()
         .branch { entry ->
             versions_file: entry instanceof Path