Use PHPStan extension installer

Author: lcobucci

composer.json

@@ -23,6 +23,7 @@
         "infection/infection": "^0.13",
         "laminas/laminas-diactoros": "^2.2",
         "lcobucci/coding-standard": "^3.0",
+        "phpstan/extension-installer": "^1.0",
         "phpstan/phpstan": "^0.12",
         "phpstan/phpstan-deprecation-rules": "^0.12",
         "phpstan/phpstan-phpunit": "^0.12",

phpstan.neon.dist

@@ -1,9 +1,3 @@
-includes:
-    - vendor/phpstan/phpstan-phpunit/extension.neon
-    - vendor/phpstan/phpstan-phpunit/rules.neon
-    - vendor/phpstan/phpstan-deprecation-rules/rules.neon
-    - vendor/phpstan/phpstan-strict-rules/rules.neon
-
 parameters:
     level: 7
     paths: