upgrade laravel to 5.6

composer.json

@@ -10,7 +10,8 @@
     "erusev/parsedown": "^1.6",
     "swiggles/memcache": "^2.0",
     "doctrine/inflector": "1.1.0",
-    "laravel/framework": "5.5.*",
+    "laravel/framework": "5.6.*",
+    "nesbot/carbon": "^1.32.0",
     "devitek/yaml-translation": "^4.1.0",
     "printempw/laravel-datatables-lite": "^1.0",
     "composer/semver": "^1.4"
@@ -19,8 +20,8 @@
     "fzaninotto/faker": "~1.4",
     "mockery/mockery": "^1.1.0",
     "phpdocumentor/reflection-docblock": "3.2.2",
-    "phpunit/phpunit": "~6.0",
-    "laravel/browser-kit-testing": "~2.0",
+    "phpunit/phpunit": "~7.0",
+    "laravel/browser-kit-testing": "~4.0",
     "barryvdh/laravel-debugbar": "^3.1.5",
     "league/flysystem-memory": "^1.0",
     "mikey179/vfsStream": "^1.6.5"