As stated in issue #27752, some Debian packages are only recommended.
As a consequence, these packages are not installed on the Official
Docker image. In that case, if the user wants to install an Odoo module
that needs one of these package, the Docker container has to be
modified.
python3-qrcode and python3-vobject are now part of the latest Debian
stable (stretch) and the latest Ubuntu LTS (Bionic Beaver).
Also, they are pure python, and very small.
Thus, the Debian package can depends on them.
co-author: @sbidoul
Fixes#27752Closes#28588Closes#28371Closes#28372