switch to flake

flake.nix

@@ -0,0 +1,19 @@
+{
+  description = "Website";
+
+  outputs = { self, nixpkgs }:
+    let pkgs = nixpkgs.legacyPackages.x86_64-linux;
+    in {
+      devShell.x86_64-linux = with pkgs;
+        mkShell {
+          nativeBuildInputs = [
+            imagemagick
+            just
+            libavif
+            libjxl
+            pandoc
+            tup
+          ];
+        };
+  };
+}