Test for Symfony 5 and 6

Author: relthyg

.github/workflows/tests.yml

@@ -16,7 +16,8 @@ jobs:
             fail-fast: false
             matrix:
                 include:
-                    - { php-version: 8.1, symfony-locked-version: none, dependency-version: prefer-stable }
+                    - { php-version: 8.1, symfony-locked-version: 5.4, dependency-version: prefer-stable }
+                    - { php-version: 8.1, symfony-locked-version: 6.4, dependency-version: prefer-stable }
         name: PHPUnit (PHP ${{matrix.php-version}}, Symfony Version Lock ${{ matrix.symfony-locked-version }}, ${{ matrix.dependency-version }})
         steps:
             -   uses: actions/checkout@v4