Update css.yml

Author: ffoodd

.github/workflows/css.yml

@@ -27,7 +27,7 @@ jobs:
       - run: npm --version
 
       - name: Set up npm cache
-        uses: actions/cache@v2
+        uses: actions/cache@v4
         with:
           path: ~/.npm
           key: ${{ runner.os }}-node-v${{ env.NODE }}-${{ hashFiles('package.json') }}-${{ hashFiles('package-lock.json') }}