Remove PHP 8.1 from CI, it's EOL on 2025.12.31. Also clean up 8.5 for now

Author: andrewmy

.github/workflows/ci.yml

@@ -10,7 +10,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        php: ['8.1', '8.2', '8.3', '8.4', '8.5']
+        php: ['8.2', '8.3', '8.4']
 
     name: PHP ${{ matrix.php }} tests