revert 8.4 addition

Author: tacman

.github/workflows/test.yml

@@ -8,7 +8,7 @@ jobs:
 
     strategy:
       matrix:
-        php-versions: ['7.4', '8.0', '8.1', '8.2', '8.3', '8.4']
+        php-versions: ['7.4', '8.0', '8.1', '8.2', '8.3']
 
     name: PHP ${{ matrix.php-versions }}