Use phpstan/extension-installer

Author: mglaman

composer.json

@@ -17,14 +17,15 @@
         "webflo/drupal-finder": "^1.2"
     },
     "require-dev": {
-        "phpstan/phpstan-strict-rules": "^1.0",
-        "squizlabs/php_codesniffer": "^3.3",
-        "phpunit/phpunit": "^6.5 || ^7.5 || ^8.0 || ^9",
-        "phpstan/phpstan-deprecation-rules": "^1.0",
         "composer/installers": "^1.9",
-        "drupal/core-recommended": "^8.8@alpha || ^9.0",
         "drupal/core-dev": "^8.8@alpha || ^9.0",
-        "drush/drush": "^9.6 | ^10.0"
+        "drupal/core-recommended": "^8.8@alpha || ^9.0",
+        "drush/drush": "^9.6 | ^10.0",
+        "phpstan/extension-installer": "^1.1",
+        "phpstan/phpstan-deprecation-rules": "^1.0",
+        "phpstan/phpstan-strict-rules": "^1.0",
+        "phpunit/phpunit": "^6.5 || ^7.5 || ^8.0 || ^9",
+        "squizlabs/php_codesniffer": "^3.3"
     },
     "minimum-stability": "dev",
     "prefer-stable": true,
@@ -65,7 +66,8 @@
     },
     "config": {
         "allow-plugins": {
-            "composer/installers": true
+            "composer/installers": true,
+            "phpstan/extension-installer": true
         }
     }
 }

phpstan.neon

@@ -1,6 +1,3 @@
-includes:
-	- vendor/phpstan/phpstan-strict-rules/rules.neon
-	- vendor/phpstan/phpstan-deprecation-rules/rules.neon
 parameters:
 	level: 8
 	checkGenericClassInNonGenericObjectType: false