Merge pull request #388 from nextcloud/dependabot/composer/phpunit/phpunit-8.5.3

Author: dependabot-preview[bot]

composer.json

@@ -10,7 +10,7 @@
     ],
     "require": {},
     "require-dev": {
-        "phpunit/phpunit": "^7.5",
+        "phpunit/phpunit": "^8.5",
         "nextcloud/coding-standard": "^0.3.0"
     },
     "scripts": {