Do not install apt-transport-https package on Debian Buster and newer

[jwarnier]

The HTTPS support for APT has been natively included in APT 1.5, hence the apt-transport-https package is empty & deprecated since Debian jumped this version (after Debian 9 Stretch, so with Debian 10 Buster).

Code which should be made conditional is here:

ansible-datadog/tasks/pkg-debian.yml

Lines 2 to 7 in a34e962

	- name: Install apt-transport-https
	apt:
	update_cache: true
	name: apt-transport-https
	state: present
	when: not ansible_check_mode