Unfortunately there is no repo for vagrant-packages to install .deb-packages from (see an ages old issue), so here's an ugly hack to install the latest version of vagrant through Ansible.
- name: Find latest vagrant-version
shell: wget -qO - https://releases.hashicorp.com/vagrant/ | grep -o 'vagrant_[[:digit:]]\.[[:digit:]]\.[[:digit:]]' | sed 's/vagrant_//'| head -1
register: vagrant_version.
- name: Install vagrant
apt:
deb: "https://releases.hashicorp.com/vagrant/{{ vagrant_version }}/vagrant_{{ vagrant_version }}_x86_64.deb"
when: ansible_os_family | lower == 'debian'
become: yes
An alternative would be to use ubuntu-ppa on Debian. Hm. Not so sure about that.
Hopefully they'll integrate vagrant into their freshly announced linux-repos some time soon...