The tag is present in Lintian version 2.109.6. That is the most recent version we know about.
The watch file specifies a githubredir.debian.net URL, which is deprecated Instead, use direct links to the tags page:
version=3 https://github.com/<user>/<project>/tags .*/(.*).tar.gz
<project> with the Github
username and project respectively.
Please refer to https://lists.debian.org/debian-devel-announce/2014/10/msg00000.html for details.