.github/workflows/pages.yml: various

- this package should always be cached, add max-jobs so job errors if it isn't

- move accept-flake-config to extra_nix_config

.github/workflows/pages.yml

@@ -23,13 +23,15 @@ jobs:
         uses: cachix/install-nix-action@v23
         with:
           extra_nix_config: |
+            accept-flake-config = true
             experimental-features = nix-command flakes
+            max-jobs = 0
       - name: Setup Pages
         id: pages
         uses: actions/configure-pages@v3
       - name: Build Pages
         run: |
-          nix build --option accept-flake-config true .#pages
+          nix build .#pages
       - name: Upload artifact
         uses: actions/upload-pages-artifact@v2
         with: