Updated to final PSR-15

Author: michalbundyra

composer.json

@@ -21,14 +21,14 @@
         "php": "^7.1",
         "ext-json": "*",
         "fig/http-message-util": "^1.1.2",
-        "http-interop/http-server-middleware": "^1.0.1",
         "psr/container": "^1.0",
         "psr/http-message": "^1.0",
+        "psr/http-server-middleware": "^1.0",
         "spatie/array-to-xml": "^2.3",
         "willdurand/negotiation": "^2.3"
     },
     "require-dev": {
-        "phpunit/phpunit": "^6.3.1",
+        "phpunit/phpunit": "^6.5.5",
         "zendframework/zend-coding-standard": "~1.0.0",
         "zendframework/zend-diactoros": "^1.4"
     },