[IMP] odoo-shippable: Add gettext as a dependency
Since MQT now requires click-odoo-makepot to construct .pot files, and
this last uses msgmerge
to merge translation messages, we need to add
gettext as a dependency, which provides that commandthe required command
This is one more step to solve https://github.com/Vauxoo/maintainer-quality-tools/issues/265