chore: Composer PHP constrain >=7.1.3

Signed-off-by: Jack Cherng <jfcherng@gmail.com>

Author: jfcherng

composer.json

@@ -26,7 +26,7 @@
         }
     },
     "require": {
-        "php": "^7.1.3"
+        "php": ">=7.1.3"
     },
     "require-dev": {
         "friendsofphp/php-cs-fixer": "^2.16",