Merge branch 'add-nix-command-and-flakes-to-ci-build' into 'main'

Add "nix-command" and "flakes" options to CI build command

See merge request !4

.gitlab-ci.yml

@@ -8,4 +8,4 @@ default:
 build:
   stage: build
   script:
-    - "nix build -Lv -f nix"
+    - nix --extra-experimental-features "nix-command flakes" build -Lv -f nix