Change minimum php version

Author: lchrusciel

composer.json

@@ -12,7 +12,7 @@
         { "name": "Jeremy Mikola", "email": "[email protected]" }
     ],
     "require": {
-        "php": ">=5.6.0",
+        "php": "^5.6.0|^7.0",
         "symfony/framework-bundle": "^3.2|^4",
         "symfony/console": "^3.2|^4",
         "symfony/dependency-injection": "^3.3|^4",