Add zip to apt_package_check_list.

It always looked weird to me that, while unzip is included into the list of packages to install, zip is not. Every now and then I end up doing an `apt-get install zip` manually, or creating a `provision-custom.sh` only to add zip to `apt_package_check_list`. I use this tool a lot, and I risk to say that I'm not the only one that can find useful to have it automatically installed.