Update composer.json and associated lock files.

Author: dmerchier

api/composer.json

@@ -4,7 +4,7 @@
     "require": {
         "php": "^7.1.3",
         "ext-iconv": "*",
-        "api-platform/api-pack": "^1.0",
+        "api-platform/api-pack": "^1.1",
         "api-platform/core": "^2.3@dev",
         "guzzlehttp/guzzle": "^6.3",
         "nelmio/cors-bundle": "^1.5",