Simplify CI config thanks to upstream changes (#15)

Author: bocharsky-bw

.github/workflows/ci.yaml

@@ -10,9 +10,6 @@ on:
 jobs:
     test:
         uses: SymfonyCasts/.github/.github/workflows/phpunit.yaml@main
-        with:
-            php-version-matrix: '["8.1", "8.2", "8.3"]'
-            php-version-lowest: '8.1'
 
     test_windows:
         uses: SymfonyCasts/.github/.github/workflows/phpunit.yaml@main