Merge pull request #139 from maxmind/dependabot/composer/phpunit/phpunit-4.staror-5.star

Update phpunit/phpunit requirement from 4.* to 4.* || 5.*

Author: oschwald

composer.json

@@ -20,7 +20,7 @@
     },
     "require-dev": {
         "friendsofphp/php-cs-fixer": "2.*",
-        "phpunit/phpunit": "4.*",
+        "phpunit/phpunit": "4.* || 5.*",
         "squizlabs/php_codesniffer": "3.*"
     },
     "autoload": {