Require PHPStan 1.8.0

Author: ondrejmirtes

composer.json

@@ -15,7 +15,7 @@
   "require": {
     "php": "^7.2 || ^8.0",
     "ext-simplexml": "*",
-    "phpstan/phpstan": "^1.6"
+    "phpstan/phpstan": "^1.8"
   },
   "conflict": {
     "symfony/framework-bundle": "<3.0"