Update PHPStan to the latest version

Author: amorimjuliana

composer.json

@@ -12,14 +12,14 @@
   ],
   "require": {
     "php": "^7.2",
-    "phpstan/phpstan": "^0.11.4"
+    "phpstan/phpstan": "^0.12"
   },
   "require-dev": {
     "phpunit/phpunit": "^8.0.4",
     "antlr/antlr4-php-runtime": "^0.3.0",
     "slevomat/coding-standard": "^5.0.4",
     "squizlabs/php_codesniffer": "^3.4.1",
-    "phpstan/phpstan-phpunit": "^0.11.2",
+    "phpstan/phpstan-phpunit": "^0.12",
     "phpstan/extension-installer": "^1.0"
   },
   "autoload": {