updated phpunit-bridge so that the lowest works

Author: Connor Graham

composer.json

@@ -31,7 +31,7 @@
         "symfony/security-bundle": "^3.3|^4.0",
         "symfony/templating": "^3.3|^4.0",
         "symfony/browser-kit": "^3.3|^4.0",
-        "symfony/phpunit-bridge": "^4.0",
+        "symfony/phpunit-bridge": "^4.2.8",
         "doctrine/orm": "^2.0"
     },
     "suggest": {