ci(composer): Set platform to 8.1.31 to allow psalm6 for PHP 8.4+8.5

Signed-off-by: Joas Schilling <coding@schilljs.com>

Author: nickvergessen

composer.json

@@ -48,7 +48,7 @@
             "ramsey/devtools": true
         },
         "platform": {
-            "php": "8.1"
+            "php": "8.1.31"
         },
         "sort-packages": true
     },