haskell-template already uses Github Actions for CI, but you may also use Garnix. Garnix is a Nix based hosted CI service that integrates well with GitHub. Compared to Github Actions, Garnix CI jobs run faster and finally you get a free Nix cache as a result (no need to manually push to cachix).
You may use the following
garnix.yaml to enable both Linux and macOS builds:
builds: include: - "*.aarch64-darwin.*" - "*.x86_64-linux.*" exclude: # https://github.com/srid/haskell-flake/issues/21 - "checks.*.main-hls"