Merge pull request #4 from sunrise-php/renovate/phpunit-phpunit-7.x

Update dependency phpunit/phpunit to v7.5.4

Author: fenric

composer.json

@@ -14,7 +14,7 @@
         "ext-intl": "*"
     },
     "require-dev": {
-        "phpunit/phpunit": "7.5.1"
+        "phpunit/phpunit": "7.5.4"
     },
     "autoload": {
         "psr-4": {