De acordo com man dh_installcron
:
--name=name
Look for files named debian/package.name.cron.* and install them as
etc/cron.*/name, instead of using the usual files and installing
them as the package name.
Portanto, nomeie seu debian/package-name.foobar.cron.d
e adicione a debian/rules
:
override_dh_installcron:
dh_installcron --name=foobar