moved flex to require instead of require-dev

Author: fabpot

composer.json

@@ -5,12 +5,12 @@
     "description": "Project description",
     "require": {
         "php": "^7.0.8",
+        "symfony/flex": "^1.0",
         "symfony/console": "^3.3",
         "symfony/framework-bundle": "^3.3",
         "symfony/yaml": "^3.3"
     },
     "require-dev": {
-        "symfony/flex": "^1.0",
         "symfony/dotenv": "^3.3"
     },
     "config": {