[TASK] Update PHPUnit and PHP_CodeSniffer (#40)

Author: oliverklee

composer.json

@@ -31,8 +31,8 @@
         "roave/security-advisories": "dev-master"
     },
     "require-dev": {
-        "phpunit/phpunit": "^6.2.2",
-        "squizlabs/php_codesniffer": "^3.0.0",
+        "phpunit/phpunit": "^6.5.0",
+        "squizlabs/php_codesniffer": "^3.2.0",
         "phpstan/phpstan": "^0.7.0",
         "nette/caching": "^2.5.0 || ^3.0.0",
         "nikic/php-parser": "^3.0.0",