Add phpstan plus official extensions

Author: spaceemotion

composer.json

@@ -13,6 +13,11 @@
  "ergebnis/composer-normalize": "^2.4",
  "php-parallel-lint/php-parallel-lint": "^1.2",
  "phpmd/phpmd": "^2.8",
+ "phpstan/phpstan": "^0.12",
+ "phpstan/phpstan-deprecation-rules": "^0.12",
+ "phpstan/phpstan-mockery": "^0.12",
+ "phpstan/phpstan-phpunit": "^0.12",
+ "phpstan/phpstan-strict-rules": "^0.12",
  "symplify/easy-coding-standard-prefixed": "^7.2"
  }
 }

phpstan.neon

@@ -0,0 +1,9 @@
+includes:
+ - vendor/phpstan/phpstan-deprecation-rules/rules.neon
+ - vendor/phpstan/phpstan-strict-rules/rules.neon
+ - vendor/phpstan/phpstan-mockery/extension.neon
+ - vendor/phpstan/phpstan-phpunit/extension.neon
+ - vendor/phpstan/phpstan-phpunit/rules.neon
+
+parameters:
+ level: max