Don't test on PHP 8.4 due to the "aura/sql" bug

Author: aik099

.github/workflows/tests.yml

@@ -21,7 +21,8 @@ jobs:
 
     strategy:
       matrix:
-        php: [ '5.6', '7.0', '7.1', '7.2', '7.3', '7.4', '8.0', '8.1', '8.2', '8.3', '8.4']
+        # Don't test on PHP 8.4 due to "aura/sql" bug: https://github.com/auraphp/Aura.Sql/pull/231.
+        php: [ '5.6', '7.0', '7.1', '7.2', '7.3', '7.4', '8.0', '8.1', '8.2', '8.3']
       fail-fast: false
 
     steps: