upgrade actions/cache to v4 in github actions

Author: Forever-CodingNoob

.github/workflows/pages.yml

@@ -19,7 +19,7 @@ jobs:
         with:
           node-version: '18'
       - name: Cache NPM dependencies
-        uses: actions/cache@v2
+        uses: actions/cache@v4
         with:
           path: node_modules
           key: ${{ runner.OS }}-npm-cache
@@ -33,4 +33,4 @@ jobs:
         uses: peaceiris/actions-gh-pages@v3
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}
-          publish_dir: ./public
+          publish_dir: ./public