You should download the update site (temporary_HiTS_util_update_site.zip) and from Help | Install New Software… | [Add…] | [Archive…] temporary_HiTS_util_update_site.zip (name it as you want)
Select and install the (single) KNIME utilities feature. ([Next] | [Next] | accept license | [Finish] | [Install Anyway] | [Restart Now].) After restart you should be able to find the Dendrogram with Heatmap node.