CI: switch to matrix based

.gitlab-ci.yml

-include:
-- remote: 'https://gitlab.horizon-haskell.net/gitlab/ci-templates/raw/master/default.yml'
+stages:
+- build
+- devour
+
+build:
+  stage: build
+  script:
+  - nix build .#packages.$SYSTEM.$PACKAGE -L
+  parallel:
+    matrix:
+      - SYSTEM:
+         - aarch64-darwin
+         - x86_64-linux
+        PACKAGE:
+         - cardano-cli
+         - cardano-node
+         - hydra-node
+
+devour:
+  stage: devour
+  script:
+  - nix build github:srid/devour-flake#packages.$SYSTEM.default -L --no-link --print-out-paths --override-input flake . --keep-going
+  parallel:
+    matrix:
+      - SYSTEM:
+         - aarch64-darwin
+         - x86_64-linux