Update dependencies

Author: sebastianbergmann

composer.json

@@ -35,7 +35,7 @@
         "ext-libxml": "*",
         "ext-xmlwriter": "*",
         "nikic/php-parser": "^5.4.0",
-        "phpunit/php-file-iterator": "^5.1.0",
+        "phpunit/php-file-iterator": "^6.0-dev",
         "phpunit/php-text-template": "^4.0.1",
         "sebastian/complexity": "^4.0.1",
         "sebastian/environment": "^7.2.0",