Update nette/tester

Author: enumag

composer.json

@@ -27,7 +27,7 @@
 		"doctrine/orm": "^2.5",
 		"symfony/validator": "^2.5.3 || ^3.0 || ^4.0",
 		"nette/bootstrap": "^2.4.5@dev",
-		"nette/tester": "^1.7"
+		"nette/tester": "^2.0"
 	},
 	"minimum-stability": "dev",
 	"conflict": {