Update run-tests.yml to include PHP 8.3 and 8.4

Author: jonnott

.github/workflows/run-tests.yml

@@ -22,7 +22,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        php: [8.1, 8.2]
+        php: [8.1, 8.2, 8.3, 8.4]
 
     name: P${{ matrix.php }}