Update cache key

Author: mvdnbrk

.github/workflows/tests.yml

@@ -44,7 +44,7 @@ jobs:
         uses: actions/cache@v2
         with:
           path: ~/.composer/cache/files
-          key: dependencies-laravel-${{ matrix.laravel }}-php-${{ matrix.php }}-composer-${{ hashFiles('composer.json') }}
+          key: dependencies-laravel-${{ matrix.laravel }}-php-${{ matrix.php }}-${{ matrix.dependency-version }}-${{ hashFiles('composer.json') }}
 
       - name: Setup PHP
         uses: shivammathur/setup-php@v2