Include php 8.4 in tests

Author: zbateson

.github/workflows/tests.yml

@@ -9,7 +9,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest, windows-latest]
-        php: [8.3, 8.2, 8.1, 8.0]
+        php: [8.4, 8.3, 8.2, 8.1, 8.0]
         stability: [prefer-stable]
 
     name: P${{ matrix.php }} - ${{ matrix.stability }} - ${{ matrix.os }}