Remove php version 8.4 from workflow tests. Not fully supported

Author: joelbladt

.github/workflows/tests.yaml

@@ -26,7 +26,7 @@ jobs:
     strategy:
       fail-fast: true
       matrix:
-        php: [8.3, 8.4]
+        php: [ 8.3 ]
         phpunit: ['11.0', '11.4', '12.2']
         phpstan: ['2.1']
         paratest: ['7.8', '7.10']