Updated to final PSR-15

Author: geerteltink

composer.json

@@ -21,12 +21,13 @@
     },
     "require": {
         "php": "^7.1",
-        "http-interop/http-server-middleware": "^1.0.1",
         "psr/container": "^1.0",
-        "psr/http-message": "^1.0.1"
+        "psr/http-message": "^1.0.1",
+        "psr/http-server-handler": "^1.0",
+        "psr/http-server-middleware": "^1.0"
     },
     "require-dev": {
-        "phpunit/phpunit": "^6.3",
+        "phpunit/phpunit": "^6.5.5",
         "roave/security-advisories": "dev-master",
         "zendframework/zend-coding-standard": "~1.0.0"
     },