Add support for PHP 7.3

Author: srenon

composer.json

@@ -13,15 +13,15 @@
         "success page js"
     ],
     "require": {
-        "php": "~5.6.0|7.0.2|7.0.4|~7.0.6|~7.1.0|~7.1.3|~7.2.0",
+        "php": "~5.6.0|7.0.2|7.0.4|~7.0.6|~7.1.0|~7.1.3|~7.2.0|~7.3.0",
         "magento/module-backend": "100.0.*|100.1.*|100.2.*|101.0.*",
         "magento/framework": "100.0.*|100.1.*|101.0.*|102.0.*"
     },
     "suggest": {
         "magepal/magento2-preview-checkout-success-page":"Preview checkout success page from admin"
     },
     "type": "magento2-module",
-    "version": "1.1.8",
+    "version": "1.1.9",
     "license": [
         "proprietary"
     ],