Update GitHub Actions cache to v4

Author: mehmetcansahin

.github/workflows/ci.yml

@@ -84,7 +84,7 @@ jobs:
         run: echo "::set-output name=dir::$(composer config cache-files-dir)"
 
       - name: Cache composer dependencies
-        uses: actions/cache@v2
+        uses: actions/cache@v4
         with:
           path: ${{ steps.composer-cache.outputs.dir }}
           key: "php-${{ matrix.php }}-laravel-${{ matrix.laravel }}-${{ hashFiles('**/composer.json') }}"