build: Use new flake check & build phases

Signed-off-by: Christoph Heiss <christoph@c8h4.io>

.build.yml

@@ -1,8 +1,7 @@
 ---
 image: nixos/unstable
-packages:
-  - nixos.hugo
-  - nixos.nodePackages.prettier
+environment:
+  NIX_CONFIG: "experimental-features = nix-command flakes"
 sources:
   - https://git.sr.ht/~c8h4/c8h4.io
 secrets:
@@ -10,11 +9,11 @@ secrets:
 tasks:
   - lint: |
       cd c8h4.io
-      prettier --check .
+      nix flake check
   - build: |
       cd c8h4.io
-      hugo --minify
+      nix build
   - deploy: |
-      tar -C c8h4.io/public -cvzf site.tar.gz .
+      tar -C c8h4.io/result -cvzf site.tar.gz .
       set +x # do not completely clobber the output with gargabe
       cat <(echo c8h4.io) <(cat site.tar.gz) | ssh -T -o StrictHostKeyChecking=no deploy@fort.c8h4.io