Bumps [cachix/install-nix-action](https://github.com/cachix/install-nix-action) from 19 to 20. - [Release notes](https://github.com/cachix/install-nix-action/releases) - [Commits](https://github.com/cachix/install-nix-action/compare/v19...v20) --- updated-dependencies: - dependency-name: cachix/install-nix-action dependency-type: direct:production update-type: version-update:semver-major ... Signed-off-by: dependabot[bot] <support@github.com>