enable all supported versions to enforce testing in CI

.github/workflows/ci.yaml

@@ -16,18 +16,8 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        php_version: ["7.1", "7.2", "7.3", "7.4"]
+        php_version: ["7.1", "7.2", "7.3", "7.4", "8.0", "8.1", "8.2", "8.3"]
     steps:
       - uses: actions/checkout@v4
       - name: Run tests
         run: make PHP_VERSION=${{ matrix.php_version }} test
-  tests-future-versions:
-    runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        php_version: ["8.0", "8.1", "8.2", "8.3"]
-    steps:
-      - uses: actions/checkout@v4
-      - name: Run tests against all major versions of PHP
-        run: make PHP_VERSION=${{ matrix.php_version }} test
-        continue-on-error: true