docker: stop using apt force

Here the desciption from Ansible docs
Corresponds to the --force-yes to apt-get and implies allow_unauthenticated: yes
This option will disable checking both the packages' signatures and the certificates of the web servers they are downloaded from.
This option *is not* the equivalent of passing the -f flag to apt-get on the command line
**This is a destructive operation with the potential to destroy your system, and it should almost never be used.** Please also see man apt-get for more information.

Signed-off-by: Etienne Champetier <champetier.etienne@gmail.com>