fix php 7 support in composer

Author: justincy

composer.json

@@ -8,7 +8,7 @@
     ],
     "license": "Apache-2.0",
     "require": {
-        "php": "^5.5"
+        "php": ">=5.5"
     },
     "require-dev": {
         "gedcomx/gedcomx-php": "^3.1.2",