fix: hugo post css (#2395)

Signed-off-by: Attila Mészáros <csviri@gmail.com>

Author: csviri

.github/workflows/hugo.yaml

@@ -50,7 +50,11 @@ jobs:
         uses: actions/configure-pages@v4
       - name: Install Node.js dependencies
         working-directory: ./docsy
-        run: "[[ -f package-lock.json || -f npm-shrinkwrap.json ]] && npm ci || true"
+        run: |          
+          [[ -f package-lock.json || -f npm-shrinkwrap.json ]] && npm ci || true
+          npm install -D autoprefixer
+          npm install -D postcss-cli
+          npm install -D postcss
       - name: Build with Hugo
         env:
           # For maximum backward compatibility with Hugo modules