By: Tom Sydney Kerckhove <syd@cs-syd.eu>
Ship the builders on the overlay, the way dekking does
The check builders were a flake output, so a consuming repository reached them
through `hopinion.lib.${system}` and had to hand back the package set it had
just built. They now hang off `pkgs.hopinion` as passthru, which is the shape
dekking uses for makeCoverageReport and the shape nix-ci already consumes.
Two things fall out. A consumer adds one overlay and calls
`pkgs.hopinion.makeHopinionCheck { src = ./.; }`, because the package set is the
one the overlay was applied to, so the argument that used to be mandatory is now
a default. And hopinion needs to be a flake at all only for its own checks: a
consumer takes it with `flake = false` and imports the overlay path, exactly as
it takes dekking.