Merge pull request #91 from prooph/dependabot/composer/phpstan/phpstan-tw-1.5

Update phpstan/phpstan requirement from ^0.12 to ^1.5

Author: Alexander Miertsch

composer.json

@@ -70,7 +70,7 @@
     "friendsofphp/php-cs-fixer": "^3.5",
     "prooph/php-cs-fixer-config": "^0.5.0",
     "matthiasnoback/symfony-dependency-injection-test": "^3.1 || ^4.1",
-    "phpstan/phpstan": "^0.12"
+    "phpstan/phpstan": "^1.5"
   },
   "minimum-stability": "dev",
   "prefer-stable": true,