[Feature request]: Add support for Flatpak and Cinnamon updates to mintupdate-cli

[git70]

In addition to the existing --only-kernel --only-security --install-recommends options, it would be ideal to be able to update Flatpak and Cinnamon Addons

[NintendoManiac64]

As a work-around, I don't suppose the existing flatpak update command works, at least for flatpak packages? It's what you had to do for manual updates prior to Mint 21.1.

I wonder if this is related to the issue #818 which I mention occurs when mintUpdate itself is unchecked in "Startup Applications"?