Laravel: fixing phan target php version to 8.1 to match composer.json. (#434)

Author: ChrisLightfootWild

.phan/config.php

@@ -42,7 +42,7 @@
     //
     // Note that the **only** effect of choosing `'5.6'` is to infer that functions removed in php 7.0 exist.
     // (See `backward_compatibility_checks` for additional options)
-    'target_php_version' => '8.0',
+    'target_php_version' => '8.1',
 
     // If enabled, missing properties will be created when
     // they are first seen. If false, we'll report an