Updated composer to make compatible with symfony 4 and PHP 7.1+

Author: terox

composer.json

@@ -11,15 +11,13 @@
     "minimum-stability": "dev",
     "prefer-stable": true,
     "require": {
-        "php": ">=5.5.3",
-        "doctrine/common": "~2.2",
-        "doctrine/orm": "~2.2",
-        "symfony/polyfill-php70": "^1.3",
-        "symfony/security": "^2.8|^3.0",
-        "symfony/options-resolver": "^2.8|^3.0",
+        "php": ">=7.1",
+        "doctrine/orm": "^2.6",
+        "symfony/security": "^3.3|^4.0",
+        "symfony/options-resolver": "^3.0|^4.0",
         "ircmaxell/random-lib": "~1.0",
-        "symfony/dependency-injection": "^2.7|^3.3",
-        "symfony/config": "^2.7|^3.3"
+        "symfony/dependency-injection": "^3.3|^4.0",
+        "symfony/config": "^3.3|^4.0"
     },
     "suggest": {
         "ramsey/uuid": "To use the UUID generator you should require this package"