cachix/cachix-action v4

cachix-action-v4

on GitHub

Add nixBuildArgs parameter

Simplify how paths are pushed

Previously we were setting up Nix build hook to make sure all paths are
synced to cachix.

This had a few flaws:

• nix-daemon had to be restarted, resulting into a few seconds extra
  setup per each build
• spurious error on macos due to nix-daemon socket not ready in time
• significant overhead since syncing to cachix was synchronous for each
  derivation built

Now we just look for new store paths and push those after nix-build.