Update ci.yml

Update runners to ubuntu-24.04

Author: pforesi

.github/workflows/ci.yml

@@ -4,7 +4,7 @@ on: [push, pull_request]
 jobs:
   tests:
     name: Tests
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-24.04
     strategy:
       matrix:
         php-version: ['8.1', '8.2']