Update GitHub Actions checkout and cache actions from v2 to v4 for improved functionality

Author: aneeskhan47

.github/workflows/tests.yml

@@ -17,10 +17,10 @@ jobs:
     steps:
 
     - name: Checkout
-      uses: actions/checkout@v2
+      uses: actions/checkout@v4
 
     - name: Cache dependencies
-      uses: actions/cache@v2
+      uses: actions/cache@v4
       with:
         path: ~/.composer/cache/files
         key: dependencies-php-${{ matrix.php }}-composer-${{ hashFiles('composer.json') }}