---
- name: Install GnuPG (to manage the APT keystore)
  become: yes
  apt:
    name: gnupg2
    state: present

- name: Install common CA certificates
  become: yes
  apt:
    name: ca-certificates
    state: present

- name: Ensure that APT can use HTTPS repositories
  become: yes
  apt:
    name: apt-transport-https
    state: present
...