allow newer versions of xeroapi/xero-php-oauth2

Author: JamesFreeman

composer.json

@@ -20,7 +20,7 @@
     ],
     "require": {
         "php": "^7.3|^8.0|^8.1",
-        "xeroapi/xero-php-oauth2": "^2.0|^3.0",
+        "xeroapi/xero-php-oauth2": "^2.0|^3.0|^4.0|^5.0|^6.0",
         "laravel/framework": "^6.0|^7.0|^8.0|^9.0|^10.0|^11.0"
     },
     "require-dev": {