Update dependencies

Author: oschwald

composer.json

@@ -14,13 +14,13 @@
     ],
     "require": {
         "maxmind-db/reader": "~1.5",
-        "maxmind/web-service-common": "~0.5",
+        "maxmind/web-service-common": "~0.6",
         "php": ">=5.6",
         "ext-json": "*"
     },
     "require-dev": {
         "friendsofphp/php-cs-fixer": "2.*",
-        "phpunit/phpunit": "^4.8.36 || 5.*",
+        "phpunit/phpunit": "5.*",
         "squizlabs/php_codesniffer": "3.*"
     },
     "autoload": {