Merge pull request #16 from pmclain/feature/php73

- Adding php7.3 support to composer.json

Author: irenelagno

composer.json

@@ -8,7 +8,7 @@
     "AFL-3.0"
   ],
   "require": {
-    "php": "~7.1.3|~7.2.0",
+    "php": "~7.1.3||~7.2.0||~7.3.0",
     "composer/composer": "^1.6",
     "symfony/console": "~4.0.0 || ~4.1.0"
   },