Fixing PHPStan rule

Author: moufmouf

composer.json

@@ -12,7 +12,7 @@
     "require": {
         "php": "^7.1",
         "phpstan/phpstan": "^0.10 | v0.11",
-        "thecodingmachine/safe": "^0.1"
+        "thecodingmachine/safe": "^0.1.11"
     },
     "require-dev": {
         "phpunit/phpunit": "^7.1",