ready made image?

[alicebob]

Hi,

thanks for this action, it seems to work well.
This pulls in Nix from nixos.org every single CI run. I know that's how many github CI actions work, but it strikes me as both needlessly slow and it's rather impolite for nixos.org. Would there be a way to specify a docker image which has nix pre-installed, and start the actions run from there?

edit: or alternatively, use the github runner cache somehow? Just caching /nix/ would already be nice, without using cachix, since it would keep the data in github.