ci: upgrade test runners

Author: g105b

.github/workflows/ci.yml

@@ -7,7 +7,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        php: [ 8.1, 8.2, 8.3 ]
+        php: [ 8.3, 8.4 ]
 
     steps:
       - uses: actions/checkout@v4