update actions/cache@v4

Author: filisko

.github/workflows/main.yaml

@@ -60,7 +60,7 @@ jobs:
                   php-version: ${{ matrix.php }}
 
             - name: Cache PHP dependencies
-              uses: actions/cache@v2
+              uses: actions/cache@v4
               with:
                   path: vendor
                   key: ${{ runner.os }}-php-${{ matrix.php }}-composer-${{ hashFiles('**/composer.json') }}