Comment 6 for bug 1862764

Can confirm all of the above.

https://fostips.com/apt-key-deprecated-right-way-add-repository
https://www.north-47.com/knowledge-base/how-to-securely-install-apps-on-debian-based-linux-distros/

With apt-key being deprecated and a transition to more secure (better) restriction of repository trust via "signed-by", we definitely need add-apt-repository to support this ASAP.

After Ubuntu 20.04 apt-key will no longer be present and well before the next LTS we need tooling/documentation to leverage the new recommended approach.