Upgrades ubuntu-20.04 to ubuntu-latest, because of the following github error:

"This is a scheduled Ubuntu 20.04 retirement. Ubuntu 20.04 LTS runner will be removed on 2025-04-15"

Author: marcing

.github/workflows/tests.yml

@@ -11,7 +11,7 @@ on:
 jobs:
   test:
     name: PHP ${{ matrix.php }}
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     strategy:
       fail-fast: false
       matrix: