Replace Snap dart-sass with npm sass in CI

Snap store is unreliable in GitHub Actions (503 errors).
Use npm install -g sass via Node 20 instead.

Author: chraibi

.github/workflows/hugo.yml

@@ -33,8 +33,12 @@ jobs:
         run: |
           wget -O ${{ runner.temp }}/hugo.deb https://github.com/gohugoio/hugo/releases/download/v${HUGO_VERSION}/hugo_extended_${HUGO_VERSION}_linux-amd64.deb \
           && sudo dpkg -i ${{ runner.temp }}/hugo.deb
+      - name: Setup Node
+        uses: actions/setup-node@v4
+        with:
+          node-version: 20
       - name: Install Dart Sass
-        run: sudo snap install dart-sass
+        run: npm install -g sass
       - name: Checkout
         uses: actions/checkout@v4
         with: