The package has a debian/watch file, but the last attempt
to use it for checking for newer upstream versions failed with
an error:
In debian/watch no matching files for watch line https://git.iem.at/pd/Gem/tags .*/-/archive/v(\d[-+_\.\da-zA-Z]*)/Gem-.*(?i)(?:\.(?:tar\.xz|tar\.bz2|tar\.gz|tar\.zstd?|zip|tgz|tbz|txz))