Add phpstan/extension-installer so that default includes are already known to PHPStan

composer.json

@@ -64,6 +64,7 @@
         "phpmetrics/phpmetrics": "^2.8",
         "phpspec/prophecy": "*",
         "phpspec/prophecy-phpunit": "*",
+        "phpstan/extension-installer": "^1.3",
         "phpstan/phpstan-deprecation-rules": "*",
         "phpunit/phpunit": "*",
         "squizlabs/php_codesniffer": "*",

defaults/phpstan.neon

@@ -14,6 +14,3 @@ parameters:
     - '#Plugin definitions cannot be altered.#'
   excludePaths:
     - '*/tests/*.php'
-includes:
-  - /var/www/html/vendor/mglaman/phpstan-drupal/extension.neon
-  - /var/www/html/vendor/phpstan/phpstan-deprecation-rules/rules.neon